diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index cdab3ba28..81818efe0 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -20,6 +20,7 @@ repos:
           - mirai
           - checkmate
           - cli
+          - htmltools
           - jsonlite
           - lifecycle
           - logger
diff --git a/DESCRIPTION b/DESCRIPTION
index 9f676084d..7c8a508ff 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -35,13 +35,14 @@ URL: https://insightsengineering.github.io/teal/,
     https://github.com/insightsengineering/teal/
 BugReports: https://github.com/insightsengineering/teal/issues
 Depends:
-    R (>= 4.0),
+    R (>= 4.1),
     shiny (>= 1.8.1),
     teal.data (>= 0.6.0.9017),
     teal.slice (>= 0.5.1.9015)
 Imports:
     checkmate (>= 2.1.0),
     cli,
+    htmltools,
     jsonlite,
     lifecycle (>= 0.2.0),
     logger (>= 0.2.0),
@@ -84,7 +85,7 @@ Config/Needs/verdepcheck: rstudio/shiny, insightsengineering/teal.data,
     rstudio/bslib, yihui/knitr, bioc::MultiAssayExperiment, r-lib/R6,
     rstudio/rmarkdown, tidyverse/rvest, rstudio/shinytest2,
     rstudio/shinyvalidate, r-lib/testthat, r-lib/withr,
-    yaml=vubiostat/r-yaml
+    yaml=vubiostat/r-yaml, rstudio/htmltools
 Config/Needs/website: insightsengineering/nesttemplate
 Encoding: UTF-8
 Language: en-US
@@ -106,6 +107,7 @@ Collate:
     'module_filter_manager.R'
     'module_init_data.R'
     'module_nested_tabs.R'
+    'module_session_info.R'
     'module_snapshot_manager.R'
     'module_teal.R'
     'module_teal_data.R'
@@ -120,6 +122,7 @@ Collate:
     'teal_data_module-eval_code.R'
     'teal_data_module-within.R'
     'teal_data_utils.R'
+    'teal_modifiers.R'
     'teal_reporter.R'
     'teal_slices-store.R'
     'teal_slices.R'
diff --git a/NAMESPACE b/NAMESPACE
index b0124abc1..ac53893f9 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -14,6 +14,7 @@ S3method(ui_teal_module,teal_module)
 S3method(ui_teal_module,teal_modules)
 S3method(within,teal_data_module)
 export(TealReportCard)
+export(add_landing_modal)
 export(as.teal_slices)
 export(as_tdata)
 export(build_app_title)
@@ -23,12 +24,16 @@ export(get_metadata)
 export(init)
 export(landing_popup_module)
 export(make_teal_transform_server)
+export(modify_footer)
+export(modify_header)
+export(modify_title)
 export(module)
 export(modules)
 export(new_tdata)
 export(report_card_template)
 export(reporter_previewer_module)
 export(show_rcode_modal)
+export(srv_session_info)
 export(srv_teal)
 export(srv_teal_with_splash)
 export(srv_transform_teal_data)
@@ -36,6 +41,7 @@ export(tdata2env)
 export(teal_data_module)
 export(teal_slices)
 export(teal_transform_module)
+export(ui_session_info)
 export(ui_teal)
 export(ui_teal_with_splash)
 export(ui_transform_teal_data)
diff --git a/NEWS.md b/NEWS.md
index fec1a3a7c..9eaf0d024 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -4,18 +4,22 @@
 
 * Possible to call `ui_teal` and `srv_teal` directly in any application by delivering `data` argument as a `reactive` returning `teal_data` object. #669
 * Since introduction of `ui_teal` and `srv_teal` functions `id` argument in `init` is being deprecated. #1438
+* Introduce `ui_session_info` and `srv_session_info` shiny module to create the user session info and teal app lockfile lockfile download button.
 * Introduced `teal_transform_module` to provide a way to interactively modify data delivered to `teal_module`'s `server` and to decorate module outputs. #1228 #1384
 * Introduced a new argument `once = FALSE` in `teal_data_module` to possibly reload data during a run time.
 * Possibility to download lockfile to restore app session for reproducibility. #479
 * Datasets which name starts with `.` are ignored when `module`'s `datanames` is set as `"all"`.
 * Added warning when reserved `datanames`, such as `all` and `.raw_data` are being used. 
+* Added `add_custom_server()` to allow adding custom server logic to the main shiny server function of a teal app.
 
 ### Breaking changes
 
 * Setting `datanames()` on `data` passed to teal application no longer has effect. In order to change `teal_module`'s 
 `datanames` one should modify `module$datanames`.
-* The `landing_popup_module()` needs to be passed as the `landing_popup` argument of `init` instead of being passed as a module of the `modules` argument of `init`.
+* `landing_popup_module()` is deprecated. Please use `add_landing_modal()` function to add a landing popup for your teal application.
 * `teal` no longer re-export `%>%`. Please load `library(magrittr)` instead or use `|>` from `base`.
+* `build_app_title` will be removed in the future release. Please use the `modify_title()` function to change the title for your teal application.
+* The `title`, `header`, and `footer` arguments of the `init()` function are deprecated. Please use the `modify_title`, `modify_header`, and `modify_footer` respectively.
 
 ### Enhancement
 
diff --git a/R/TealAppDriver.R b/R/TealAppDriver.R
index f170e515a..af78b8759 100644
--- a/R/TealAppDriver.R
+++ b/R/TealAppDriver.R
@@ -26,7 +26,8 @@ TealAppDriver <- R6::R6Class( # nolint: object_name.
     #' @description
     #' Initialize a `TealAppDriver` object for testing a `teal` application.
     #'
-    #' @param data,modules,filter,title,header,footer,landing_popup arguments passed to `init`
+    #' @param data,modules,filter arguments passed to `init`
+    #' @param title_args,header,footer,landing_popup_args to pass into the modifier functions.
     #' @param timeout (`numeric`) Default number of milliseconds for any timeout or
     #' timeout_ parameter in the `TealAppDriver` class.
     #' Defaults to 20s.
@@ -45,25 +46,51 @@ TealAppDriver <- R6::R6Class( # nolint: object_name.
     initialize = function(data,
                           modules,
                           filter = teal_slices(),
-                          title = build_app_title(),
+                          title_args = list(),
                           header = tags$p(),
                           footer = tags$p(),
-                          landing_popup = NULL,
+                          landing_popup_args = NULL,
                           timeout = rlang::missing_arg(),
                           load_timeout = rlang::missing_arg(),
                           ...) {
       private$data <- data
       private$modules <- modules
       private$filter <- filter
+
+      new_title <- modifyList(
+        list(
+          title = "Custom Teal App Title",
+          favicon = "https://raw.githubusercontent.com/insightsengineering/hex-stickers/main/PNG/teal.png"
+        ),
+        title_args
+      )
       app <- init(
         data = data,
         modules = modules,
-        filter = filter,
-        title = title,
-        header = header,
-        footer = footer,
-        landing_popup = landing_popup,
-      )
+        filter = filter
+      ) |>
+        modify_title(title = new_title$title, favicon = new_title$favicon) |>
+        modify_header(header) |>
+        modify_footer(footer)
+
+      if (!is.null(landing_popup_args)) {
+        default_args <- list(
+          title = NULL,
+          content = NULL,
+          footer = modalButton("Accept")
+        )
+        landing_popup_args[names(default_args)] <- Map(
+          function(x, y) if (is.null(y)) x else y,
+          default_args,
+          landing_popup_args[names(default_args)]
+        )
+        app <- add_landing_modal(
+          app,
+          title = landing_popup_args$title,
+          content = landing_popup_args$content,
+          footer = landing_popup_args$footer
+        )
+      }
 
       # Default timeout is hardcoded to 4s in shinytest2:::resolve_timeout
       # It must be set as parameter to the AppDriver
diff --git a/R/init.R b/R/init.R
index ddc2f0c44..417d0e5c4 100644
--- a/R/init.R
+++ b/R/init.R
@@ -19,21 +19,25 @@
 #'   more details.
 #' @param filter (`teal_slices`) Optionally,
 #'   specifies the initial filter using [teal_slices()].
-#' @param title (`shiny.tag` or `character(1)`) Optionally,
+#' @param title (`shiny.tag` or `character(1)`) `r lifecycle::badge("deprecated")` Optionally,
 #'   the browser window title. Defaults to a title "teal app" with the icon of NEST.
 #'   Can be created using the `build_app_title()` or
 #'   by passing a valid `shiny.tag` which is a head tag with title and link tag.
-#' @param header (`shiny.tag` or `character(1)`) Optionally,
+#'   This parameter is deprecated. Use `modify_title()` on the teal app object instead.
+#' @param header (`shiny.tag` or `character(1)`) `r lifecycle::badge("deprecated")` Optionally,
 #'   the header of the app.
-#' @param footer (`shiny.tag` or `character(1)`) Optionally,
+#'   This parameter is deprecated. Use `modify_header()` on the teal app object instead.
+#' @param footer (`shiny.tag` or `character(1)`) `r lifecycle::badge("deprecated")` Optionally,
 #'   the footer of the app.
+#'   This parameter is deprecated. Use `modify_footer()` on the teal app object instead.
+#' @param id `r lifecycle::badge("deprecated")` (`character`) Optionally,
+#'   a string specifying the `shiny` module id in cases it is used as a `shiny` module
+#'   rather than a standalone `shiny` app. This is a legacy feature. Deprecated since v0.15.3
+#'   please use [ui_teal()] and [srv_teal()] instead.
 #' @param id `r lifecycle::badge("deprecated")` (`character`) Optionally,
 #'   a string specifying the `shiny` module id in cases it is used as a `shiny` module
 #'   rather than a standalone `shiny` app. This is a legacy feature. Deprecated since v0.15.3
 #'   please use [ui_teal()] and [srv_teal()] instead.
-#'
-#' @param landing_popup (`teal_module_landing`) Optionally,
-#'   a `landing_popup_module` to show up as soon as the teal app is initialized.
 #'
 #' @return Named list containing server and UI functions.
 #'
@@ -83,10 +87,7 @@
 #'       `Iris Sepal.Length histogram` = "new_iris Species",
 #'       global_filters = "new_mtcars cyl"
 #'     )
-#'   ),
-#'   title = "App title",
-#'   header = tags$h1("Sample App"),
-#'   footer = tags$p("Sample footer")
+#'   )
 #' )
 #' if (interactive()) {
 #'   shinyApp(app$ui, app$server)
@@ -95,17 +96,15 @@
 init <- function(data,
                  modules,
                  filter = teal_slices(),
-                 title = build_app_title(),
-                 header = tags$p(),
-                 footer = tags$p(),
-                 id = lifecycle::deprecated(),
-                 landing_popup = NULL) {
+                 title = lifecycle::deprecated(),
+                 header = lifecycle::deprecated(),
+                 footer = lifecycle::deprecated(),
+                 id = lifecycle::deprecated()) {
   logger::log_debug("init initializing teal app with: data ('{ class(data) }').")
 
   # argument checking (independent)
   ## `data`
   checkmate::assert_multi_class(data, c("teal_data", "teal_data_module"))
-  checkmate::assert_class(landing_popup, "teal_module_landing", null.ok = TRUE)
 
   ## `modules`
   checkmate::assert(
@@ -123,44 +122,9 @@ init <- function(data,
   ## `filter`
   checkmate::assert_class(filter, "teal_slices")
 
-  ## all other arguments
-  checkmate::assert(
-    .var.name = "title",
-    checkmate::check_string(title),
-    checkmate::check_multi_class(title, c("shiny.tag", "shiny.tag.list", "html"))
-  )
-  checkmate::assert(
-    .var.name = "header",
-    checkmate::check_string(header),
-    checkmate::check_multi_class(header, c("shiny.tag", "shiny.tag.list", "html"))
-  )
-  checkmate::assert(
-    .var.name = "footer",
-    checkmate::check_string(footer),
-    checkmate::check_multi_class(footer, c("shiny.tag", "shiny.tag.list", "html"))
-  )
-
   # log
   teal.logger::log_system_info()
 
-  # argument transformations
-  ## `modules` - landing module
-  landing <- extract_module(modules, "teal_module_landing")
-  if (length(landing) == 1L) {
-    landing_popup <- landing[[1L]]
-    modules <- drop_module(modules, "teal_module_landing")
-    lifecycle::deprecate_soft(
-      when = "0.15.3",
-      what = "landing_popup_module()",
-      details = paste(
-        "Pass `landing_popup_module` to the `landing_popup` argument of the `init` ",
-        "instead of wrapping it into `modules()` and passing to the `modules` argument"
-      )
-    )
-  } else if (length(landing) > 1L) {
-    stop("Only one `landing_popup_module` can be used.")
-  }
-
   ## `filter` - set app_id attribute unless present (when restoring bookmark)
   if (is.null(attr(filter, "app_id", exact = TRUE))) attr(filter, "app_id") <- create_app_id(data, modules)
 
@@ -222,6 +186,11 @@ init <- function(data,
     )
   }
 
+  # argument transformations
+  ## `modules` - landing module
+  landing <- extract_module(modules, "teal_module_landing")
+  modules <- drop_module(modules, "teal_module_landing")
+
 
   if (lifecycle::is_present(id)) {
     lifecycle::deprecate_soft(
@@ -237,25 +206,94 @@ init <- function(data,
     id <- character(0)
   }
   ns <- NS(id)
+
   # Note: UI must be a function to support bookmarking.
-  res <- list(
-    ui = function(request) {
-      ui_teal(
-        id = ns("teal"),
-        modules = modules,
-        title = title,
-        header = header,
-        footer = footer
-      )
-    },
-    server = function(input, output, session) {
-      if (!is.null(landing_popup)) {
-        do.call(landing_popup$server, c(list(id = "landing_module_shiny_id"), landing_popup$server_args))
+  res <- structure(
+    list(
+      ui = function(request) {
+        fluidPage(
+          title = tags$div(
+            id = "teal-app-title",
+            tags$head(
+              tags$title("teal app"),
+              tags$link(
+                rel = "icon",
+                href = "https://raw.githubusercontent.com/insightsengineering/hex-stickers/main/PNG/nest.png",
+                sizes = "any"
+              )
+            )
+          ),
+          tags$header(
+            id = "teal-header",
+            tags$div(id = "teal-header-content")
+          ),
+          ui_teal(
+            id = "teal",
+            modules = modules
+          ),
+          tags$footer(
+            id = "teal-footer",
+            tags$div(id = "teal-footer-content"),
+            ui_session_info("teal-footer-session_info")
+          )
+        )
+      },
+      server = function(input, output, session) {
+        srv_teal(id = "teal", data = data, modules = modules, filter = deep_copy_filter(filter))
+        srv_session_info("teal-footer-session_info")
       }
-      srv_teal(id = ns("teal"), data = data, modules = modules, filter = deep_copy_filter(filter))
-    }
+    ),
+    class = "teal_app"
   )
 
+  if (lifecycle::is_present(title)) {
+    checkmate::assert_multi_class(title, c("shiny.tag", "shiny.tag.list", "html", "character"))
+    lifecycle::deprecate_warn(
+      when = "0.15.3",
+      what = "init(title)",
+      details = "Use `modify_title()` on the teal app object instead."
+    )
+    res <- modify_title(res, title)
+  }
+  if (lifecycle::is_present(header)) {
+    checkmate::assert_multi_class(header, c("shiny.tag", "shiny.tag.list", "html", "character"))
+    lifecycle::deprecate_warn(
+      when = "0.15.3",
+      what = "init(header)",
+      details = paste(
+        "Use `modify_header()` on the teal app object instead."
+      )
+    )
+    res <- modify_header(res, header)
+  }
+  if (lifecycle::is_present(footer)) {
+    checkmate::assert_multi_class(footer, c("shiny.tag", "shiny.tag.list", "html", "character"))
+    lifecycle::deprecate_warn(
+      when = "0.15.3",
+      what = "init(footer)",
+      details = paste(
+        "Use `modify_footer()` on the teal app object instead."
+      )
+    )
+    res <- modify_footer(res, footer)
+  }
+
+  if (length(landing) == 1L) {
+    res <- teal_extend_server(res, function(input, output, session) {
+      do.call(landing[[1L]]$server, c(list(id = "landing_module_shiny_id")))
+    })
+    lifecycle::deprecate_warn(
+      when = "0.15.3",
+      what = "landing_popup_module()",
+      details = paste(
+        "landing_popup_module() is deprecated.",
+        "Use add_landing_modal() on the teal app object instead."
+      )
+    )
+  } else if (length(landing) > 1L) {
+    stop("Only one `landing_popup_module` can be used.")
+  }
+
   logger::log_debug("init teal app has been initialized.")
 
   res
diff --git a/R/landing_popup_module.R b/R/landing_popup_module.R
index 2876a9f1e..204c0e18e 100644
--- a/R/landing_popup_module.R
+++ b/R/landing_popup_module.R
@@ -1,9 +1,10 @@
 #' Landing popup module
 #'
-#' @description Creates a landing welcome popup for `teal` applications.
+#' @description `r lifecycle::badge("deprecated")` Creates a landing welcome popup for `teal` applications.
 #'
 #' This module is used to display a popup dialog when the application starts.
 #' The dialog blocks access to the application and must be closed with a button before the application can be viewed.
+#' This function is deprecated, please use `add_landing_modal()` on the teal app object instead.
 #'
 #' @param label (`character(1)`) Label of the module.
 #' @param title (`character(1)`) Text to be displayed as popup title.
@@ -13,51 +14,19 @@
 #'
 #' @return A `teal_module` (extended with `teal_landing_module` class) to be used in `teal` applications.
 #'
-#' @examples
-#' app1 <- init(
-#'   data = teal_data(iris = iris),
-#'   modules = modules(
-#'     example_module()
-#'   ),
-#'   landing_popup = landing_popup_module(
-#'     content = "A place for the welcome message or a disclaimer statement.",
-#'     buttons = modalButton("Proceed")
-#'   )
-#' )
-#' if (interactive()) {
-#'   shinyApp(app1$ui, app1$server)
-#' }
-#'
-#' app2 <- init(
-#'   data = teal_data(iris = iris),
-#'   modules = modules(
-#'     example_module()
-#'   ),
-#'   landing_popup = landing_popup_module(
-#'     title = "Welcome",
-#'     content = tags$b(
-#'       "A place for the welcome message or a disclaimer statement.",
-#'       style = "color: red;"
-#'     ),
-#'     buttons = tagList(
-#'       modalButton("Proceed"),
-#'       actionButton("read", "Read more",
-#'         onclick = "window.open('http://google.com', '_blank')"
-#'       ),
-#'       actionButton("close", "Reject", onclick = "window.close()")
-#'     )
-#'   )
-#' )
-#'
-#' if (interactive()) {
-#'   shinyApp(app2$ui, app2$server)
-#' }
-#'
 #' @export
 landing_popup_module <- function(label = "Landing Popup",
                                  title = NULL,
                                  content = NULL,
                                  buttons = modalButton("Accept")) {
+  lifecycle::deprecate_soft(
+    when = "0.15.3",
+    what = "landing_popup_module()",
+    details = paste(
+      "landing_popup_module() is deprecated.",
+      "Use add_landing_modal() on the teal app object instead."
+    )
+  )
   checkmate::assert_string(label)
   checkmate::assert_string(title, null.ok = TRUE)
   checkmate::assert_multi_class(
@@ -70,6 +39,7 @@ landing_popup_module <- function(label = "Landing Popup",
 
   module <- module(
     label = label,
+    datanames = NULL,
     server = function(id) {
       moduleServer(id, function(input, output, session) {
         showModal(
diff --git a/R/module_session_info.R b/R/module_session_info.R
new file mode 100644
index 000000000..682283ada
--- /dev/null
+++ b/R/module_session_info.R
@@ -0,0 +1,54 @@
+#' `teal` user session info module
+#'
+#' Module to display the user session info popup and to download a lockfile.
+#'
+#' @rdname module_session_info
+#' @name module_session_info
+#'
+#' @inheritParams module_teal
+#'
+#' @examples
+#' ui <- fluidPage(
+#'   ui_session_info("session_info")
+#' )
+#'
+#' server <- function(input, output, session) {
+#'   srv_session_info("session_info")
+#' }
+#'
+#' if (interactive()) {
+#'   shinyApp(ui, server)
+#' }
+#'
+#' @return `NULL` invisibly
+NULL
+
+#' @rdname module_session_info
+#' @export
+ui_session_info <- function(id) {
+  ns <- NS(id)
+  tags$div(
+    teal.widgets::verbatim_popup_ui(ns("sessionInfo"), "Session Info", type = "link"),
+    br(),
+    ui_teal_lockfile(ns("lockfile")),
+    textOutput(ns("identifier"))
+  )
+}
+
+#' @rdname module_session_info
+#' @export
+srv_session_info <- function(id) {
+  moduleServer(id, function(input, output, session) {
+    srv_teal_lockfile("lockfile")
+
+    output$identifier <- renderText(
+      paste0("Pid:", Sys.getpid(), " Token:", substr(session$token, 25, 32))
+    )
+
+    teal.widgets::verbatim_popup_srv(
+      "sessionInfo",
+      verbatim_content = utils::capture.output(utils::sessionInfo()),
+      title = "SessionInfo"
+    )
+  })
+}
diff --git a/R/module_teal.R b/R/module_teal.R
index f4e63fadf..d78e7eb94 100644
--- a/R/module_teal.R
+++ b/R/module_teal.R
@@ -2,11 +2,12 @@
 #'
 #' @description
 #' `r lifecycle::badge("stable")`
-#' Module to create a `teal` app. This module can be called directly instead of [init()] and
-#' included in your custom application. Please note that [init()] adds `reporter_previewer_module`
-#' automatically, which is not a case when calling `ui/srv_teal` directly.
+#' Module to create a `teal` app as a Shiny Module.
 #'
 #' @details
+#' This module can be used instead of [init()] in custom Shiny applications. Unlike [init()], it doesn't
+#' automatically include `reporter_previewer_module`, `module_session_info`, or UI components like
+#' `header`, `footer`, and `title` which can be added separately in the Shiny app consuming this module.
 #'
 #' Module is responsible for creating the main `shiny` app layout and initializing all the necessary
 #' components. This module establishes reactive connection between the input `data` and every other
@@ -36,48 +37,19 @@
 #' @param id (`character(1)`) `shiny` module instance id.
 #' @param data (`teal_data`, `teal_data_module`, or `reactive` returning `teal_data`)
 #' The data which application will depend on.
+#' @param modules (`teal_modules`)
+#'   `teal_modules` object. These are the specific output modules which
+#'   will be displayed in the `teal` application. See [modules()] and [module()] for
+#'   more details.
 #'
 #' @return `NULL` invisibly
 NULL
 
 #' @rdname module_teal
 #' @export
-ui_teal <- function(id,
-                    modules,
-                    title = build_app_title(),
-                    header = tags$p(),
-                    footer = tags$p()) {
+ui_teal <- function(id, modules) {
   checkmate::assert_character(id, max.len = 1, any.missing = FALSE)
-  checkmate::assert(
-    .var.name = "title",
-    checkmate::check_string(title),
-    checkmate::check_multi_class(title, c("shiny.tag", "shiny.tag.list", "html"))
-  )
-  checkmate::assert(
-    .var.name = "header",
-    checkmate::check_string(header),
-    checkmate::check_multi_class(header, c("shiny.tag", "shiny.tag.list", "html"))
-  )
-  checkmate::assert(
-    .var.name = "footer",
-    checkmate::check_string(footer),
-    checkmate::check_multi_class(footer, c("shiny.tag", "shiny.tag.list", "html"))
-  )
-
-  if (is.character(title)) {
-    title <- build_app_title(title)
-  } else {
-    validate_app_title_tag(title)
-  }
-
-  if (checkmate::test_string(header)) {
-    header <- tags$p(header)
-  }
-
-  if (checkmate::test_string(footer)) {
-    footer <- tags$p(footer)
-  }
-
+  checkmate::assert_class(modules, "teal_modules")
   ns <- NS(id)
 
   # show busy icon when `shiny` session is busy computing stuff
@@ -94,10 +66,8 @@ ui_teal <- function(id,
 
   fluidPage(
     id = id,
-    title = title,
     theme = get_teal_bs_theme(),
     include_teal_css_js(),
-    tags$header(header),
     tags$hr(class = "my-2"),
     shiny_busy_message_panel,
     tags$div(
@@ -132,16 +102,7 @@ ui_teal <- function(id,
         )
       )
     ),
-    tags$hr(),
-    tags$footer(
-      tags$div(
-        footer,
-        teal.widgets::verbatim_popup_ui(ns("sessionInfo"), "Session Info", type = "link"),
-        br(),
-        ui_teal_lockfile(ns("lockfile")),
-        textOutput(ns("identifier"))
-      )
-    )
+    tags$hr()
   )
 }
 
@@ -160,18 +121,6 @@ srv_teal <- function(id, data, modules, filter = teal_slices()) {
       shinyjs::showLog()
     }
 
-    srv_teal_lockfile("lockfile")
-
-    output$identifier <- renderText(
-      paste0("Pid:", Sys.getpid(), " Token:", substr(session$token, 25, 32))
-    )
-
-    teal.widgets::verbatim_popup_srv(
-      "sessionInfo",
-      verbatim_content = utils::capture.output(utils::sessionInfo()),
-      title = "SessionInfo"
-    )
-
     # `JavaScript` code
     run_js_files(files = "init.js")
 
diff --git a/R/module_teal_with_splash.R b/R/module_teal_with_splash.R
index c4f29c0ae..7794f7ccb 100644
--- a/R/module_teal_with_splash.R
+++ b/R/module_teal_with_splash.R
@@ -5,6 +5,7 @@
 #'
 #' @inheritParams ui_teal
 #' @inheritParams srv_teal
+#' @inheritParams init
 #'
 #' @return
 #' Returns a `reactive` expression containing a `teal_data` object when data is loaded or `NULL` when it is not.
@@ -16,24 +17,46 @@ NULL
 #' @rdname module_teal_with_splash
 ui_teal_with_splash <- function(id,
                                 data,
+                                modules,
                                 title = build_app_title(),
                                 header = tags$p(),
                                 footer = tags$p()) {
   lifecycle::deprecate_soft(
-    when = "0.16",
+    when = "0.15.3",
     what = "ui_teal_with_splash()",
     details = "Deprecated, please use `ui_teal` instead"
   )
-  ui_teal(id = id, title = title, header = header, footer = footer)
+  ns <- shiny::NS(id)
+  fluidPage(
+    title = tags$div(
+      id = ns("teal-app-title"),
+      tags$head(
+        tags$title("teal app"),
+        tags$link(
+          rel = "icon",
+          href = "https://raw.githubusercontent.com/insightsengineering/hex-stickers/main/PNG/nest.png",
+          sizes = "any"
+        )
+      )
+    ),
+    tags$header(id = ns("teal-header-content")),
+    ui_teal(id = id, modules = modules),
+    tags$footer(
+      id = "teal-footer",
+      tags$div(id = "teal-footer-content"),
+      ui_session_info(ns("teal-footer-session_info"))
+    )
+  )
 }
 
 #' @export
 #' @rdname module_teal_with_splash
 srv_teal_with_splash <- function(id, data, modules, filter = teal_slices()) {
   lifecycle::deprecate_soft(
-    when = "0.16",
+    when = "0.15.3",
     what = "srv_teal_with_splash()",
     details = "Deprecated, please use `srv_teal` instead"
   )
   srv_teal(id = id, data = data, modules = modules, filter = filter)
+  srv_session_info("teal-footer-session_info")
 }
diff --git a/R/show_rcode_modal.R b/R/show_rcode_modal.R
index 0f7fe8822..83bd248a9 100644
--- a/R/show_rcode_modal.R
+++ b/R/show_rcode_modal.R
@@ -15,7 +15,7 @@
 #' @export
 show_rcode_modal <- function(title = NULL, rcode, session = getDefaultReactiveDomain()) {
   lifecycle::deprecate_soft(
-    when = "0.16",
+    when = "0.15.3",
     what = "show_rcode_modal()",
     details = "This function will be removed in the next release."
   )
diff --git a/R/tdata.R b/R/tdata.R
index bb020c99f..dc79693bf 100644
--- a/R/tdata.R
+++ b/R/tdata.R
@@ -52,7 +52,7 @@ as_tdata <- function(...) {
 
 .deprecate_tdata_msg <- function() {
   lifecycle::deprecate_stop(
-    when = "0.16",
+    when = "0.15.3",
     what = "tdata()",
     details = paste(
       "tdata has been removed in favour of `teal_data`.\n",
diff --git a/R/teal_modifiers.R b/R/teal_modifiers.R
new file mode 100644
index 000000000..3f0fb90f1
--- /dev/null
+++ b/R/teal_modifiers.R
@@ -0,0 +1,191 @@
+#' Replace UI Elements in `teal` UI objects
+#'
+#' @param x (`teal_app`) A `teal_app` object created using the `init` function.
+#' @param element Replacement UI element (shiny tag or HTML)
+#' @param title (`shiny.tag` or `character(1)`) The new title to be used.
+#' @param favicon (`character`) The path for the icon for the title.
+#' The image/icon path can be remote or the static path accessible by `shiny`, like the `www/`
+#' @name teal_modifiers
+#' @rdname teal_modifiers
+#'
+#' @keywords internal
+#'
+NULL
+
+
+#' @rdname teal_modifiers
+#' @keywords internal
+#' @noRd
+#' @param x One of:
+#'   - A `teal_app` object created using the `init` function.
+#'   - A `teal_module`, `teal_data_module`, or `teal_transform_module` object.
+#'   - A Shiny module UI function with `id` parameter
+#' @param selector (`character(1)`) CSS selector to find elements to replace
+teal_replace_ui <- function(x, selector, element) {
+  if (inherits(x, c("teal_app", "teal_module", "teal_data_module", "teal_transform_module"))) {
+    x$ui <- teal_replace_ui(x$ui, selector, element)
+    x
+  } else if (checkmate::test_function(x, args = "request")) {
+    # shiny ui function from teal_app
+    function(request) {
+      ui_tq <- htmltools::tagQuery(x(request = request))
+      ui_tq$find(selector)$empty()$append(element)$allTags()
+    }
+  } else if (checkmate::test_function(x, args = "id")) {
+    # shiny module ui function
+    function(id, ...) {
+      ui_tq <- htmltools::tagQuery(x(id = id, ...))
+      if (grepl("^#[a-zA-Z0-9_-]+$", selector)) {
+        selector <- paste0("#", NS(id, gsub("^#", "", selector)))
+      }
+      ui_tq$find(selector)$empty()$append(element)$allTags()
+    }
+  } else {
+    stop("Invalid UI object")
+  }
+}
+
+#' @rdname teal_modifiers
+#' @export
+#' @examples
+#' app <- init(
+#'   data = teal_data(IRIS = iris, MTCARS = mtcars),
+#'   modules = modules(example_module())
+#' ) |>
+#'   modify_title(title = "Custom title")
+#'
+#' if (interactive()) {
+#'   shinyApp(app$ui, app$server)
+#' }
+modify_title <- function(
+    x,
+    title = "teal app",
+    favicon = "https://raw.githubusercontent.com/insightsengineering/hex-stickers/main/PNG/nest.png") {
+  checkmate::assert_multi_class(x, "teal_app")
+  checkmate::assert_multi_class(title, c("shiny.tag", "shiny.tag.list", "html", "character"))
+  checkmate::assert_string(favicon)
+  teal_replace_ui(
+    x,
+    "#teal-app-title",
+    tags$head(
+      tags$title(title),
+      tags$link(
+        rel = "icon",
+        href = favicon,
+        sizes = "any"
+      )
+    )
+  )
+}
+
+#' @rdname teal_modifiers
+#' @export
+#' @examples
+#' app <- init(
+#'   data = teal_data(IRIS = iris),
+#'   modules = modules(example_module())
+#' ) |>
+#'   modify_header(element = tags$div(h3("Custom header")))
+#'
+#' if (interactive()) {
+#'   shinyApp(app$ui, app$server)
+#' }
+modify_header <- function(x, element = tags$p()) {
+  checkmate::assert_multi_class(x, "teal_app")
+  checkmate::assert_multi_class(element, c("shiny.tag", "shiny.tag.list", "html", "character"))
+  teal_replace_ui(x, "#teal-header-content", element)
+}
+
+#' @rdname teal_modifiers
+#' @export
+#' @examples
+#' app <- init(
+#'   data = teal_data(IRIS = iris),
+#'   modules = modules(example_module())
+#' ) |>
+#'   modify_footer(element = "Custom footer")
+#'
+#' if (interactive()) {
+#'   shinyApp(app$ui, app$server)
+#' }
+modify_footer <- function(x, element = tags$p()) {
+  checkmate::assert_multi_class(x, "teal_app")
+  checkmate::assert_multi_class(element, c("shiny.tag", "shiny.tag.list", "html", "character"))
+  teal_replace_ui(x, "#teal-footer-content", element)
+}
+
+#' Add a Landing Popup to `teal` Application
+#'
+#' @description Adds a landing popup to the `teal` app. This popup will be shown when the app starts.
+#' The dialog must be closed by the app user to proceed to the main application.
+#'
+#' @param x (`teal_app`) A `teal_app` object created using the `init` function.
+#' @inheritParams shiny::modalDialog
+#' @param content (`character(1)`, `shiny.tag` or `shiny.tag.list`) with the content of the popup.
+#' @param ... Additional arguments to [shiny::modalDialog()].
+#' @export
+#' @examples
+#' app <- init(
+#'   data = teal_data(IRIS = iris, MTCARS = mtcars),
+#'   modules = modules(example_module())
+#' ) |>
+#'   add_landing_modal(
+#'     title = "Welcome",
+#'     content = "This is a landing popup.",
+#'     buttons = modalButton("Accept")
+#'   )
+#'
+#' if (interactive()) {
+#'   shinyApp(app$ui, app$server)
+#' }
+add_landing_modal <- function(
+    x,
+    title = NULL,
+    content = NULL,
+    footer = modalButton("Accept"),
+    ...) {
+  checkmate::assert_class(x, "teal_app")
+  custom_server <- function(input, output, session) {
+    checkmate::assert_string(title, null.ok = TRUE)
+    checkmate::assert_multi_class(
+      content,
+      classes = c("character", "shiny.tag", "shiny.tag.list", "html"), null.ok = TRUE
+    )
+    checkmate::assert_multi_class(footer, classes = c("shiny.tag", "shiny.tag.list"))
+    showModal(
+      modalDialog(
+        id = "landingpopup",
+        title = title,
+        content,
+        footer = footer,
+        ...
+      )
+    )
+  }
+  teal_extend_server(x, custom_server)
+}
+
+#' Add a Custom Server Logic to `teal` Application
+#'
+#' @description Adds a custom server function to the `teal` app. This function can define additional server logic.
+#'
+#' @param x (`teal_app`) A `teal_app` object created using the `init` function.
+#' @param custom_server (`function(input, output, session)` or `function(id, ...)`)
+#'    The custom server function or server module to set.
+#' @param module_id (`character(1)`) The ID of the module when a module server function is passed.
+#' @keywords internal
+teal_extend_server <- function(x, custom_server, module_id = character(0)) {
+  checkmate::assert_class(x, "teal_app")
+  checkmate::assert_function(custom_server)
+  old_server <- x$server
+
+  x$server <- function(input, output, session) {
+    old_server(input, output, session)
+    if (all(c("input", "output", "session") %in% names(formals(custom_server)))) {
+      callModule(custom_server, module_id)
+    } else if ("id" %in% names(formals(custom_server))) {
+      custom_server(module_id)
+    }
+  }
+  x
+}
diff --git a/R/utils.R b/R/utils.R
index 46fcddc1a..0f06e1e48 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -315,6 +315,11 @@ build_app_title <- function(
     favicon = "https://raw.githubusercontent.com/insightsengineering/hex-stickers/main/PNG/nest.png") {
   checkmate::assert_string(title, null.ok = TRUE)
   checkmate::assert_string(favicon, null.ok = TRUE)
+  lifecycle::deprecate_soft(
+    when = "0.15.3",
+    what = "build_app_title()",
+    details = "Use `modify_title()` on the object created using the `init`."
+  )
   tags$head(
     tags$title(title),
     tags$link(
diff --git a/_pkgdown.yml b/_pkgdown.yml
index 94e595d09..1eea00f5f 100644
--- a/_pkgdown.yml
+++ b/_pkgdown.yml
@@ -105,9 +105,17 @@ reference:
       - make_teal_transform_server
       - module_teal_with_splash
       - module_teal
+      - module_session_info
       - module
       - modules
       - teal_slices
+  - title: Application modifiers for `teal`
+    desc: Functions to modify the `teal` app object
+    contents:
+      - modify_footer
+      - modify_header
+      - modify_title
+      - add_landing_modal
   - title: Helper Functions
     desc: Helper functions for `teal`
     contents:
diff --git a/man/TealAppDriver.Rd b/man/TealAppDriver.Rd
index cfdd8110d..438a12409 100644
--- a/man/TealAppDriver.Rd
+++ b/man/TealAppDriver.Rd
@@ -98,10 +98,10 @@ Initialize a \code{TealAppDriver} object for testing a \code{teal} application.
   data,
   modules,
   filter = teal_slices(),
-  title = build_app_title(),
+  title_args = list(),
   header = tags$p(),
   footer = tags$p(),
-  landing_popup = NULL,
+  landing_popup_args = NULL,
   timeout = rlang::missing_arg(),
   load_timeout = rlang::missing_arg(),
   ...
@@ -111,7 +111,9 @@ Initialize a \code{TealAppDriver} object for testing a \code{teal} application.
 \subsection{Arguments}{
 \if{html}{\out{<div class="arguments">}}
 \describe{
-\item{\code{data, modules, filter, title, header, footer, landing_popup}}{arguments passed to \code{init}}
+\item{\code{data, modules, filter}}{arguments passed to \code{init}}
+
+\item{\code{title_args, header, footer, landing_popup_args}}{to pass into the modifier functions.}
 
 \item{\code{timeout}}{(\code{numeric}) Default number of milliseconds for any timeout or
 timeout_ parameter in the \code{TealAppDriver} class.
diff --git a/man/add_landing_modal.Rd b/man/add_landing_modal.Rd
new file mode 100644
index 000000000..be8d6339c
--- /dev/null
+++ b/man/add_landing_modal.Rd
@@ -0,0 +1,44 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/teal_modifiers.R
+\name{add_landing_modal}
+\alias{add_landing_modal}
+\title{Add a Landing Popup to \code{teal} Application}
+\usage{
+add_landing_modal(
+  x,
+  title = NULL,
+  content = NULL,
+  footer = modalButton("Accept"),
+  ...
+)
+}
+\arguments{
+\item{x}{(\code{teal_app}) A \code{teal_app} object created using the \code{init} function.}
+
+\item{title}{An optional title for the dialog.}
+
+\item{content}{(\code{character(1)}, \code{shiny.tag} or \code{shiny.tag.list}) with the content of the popup.}
+
+\item{footer}{UI for footer. Use \code{NULL} for no footer.}
+
+\item{...}{Additional arguments to \code{\link[shiny:modalDialog]{shiny::modalDialog()}}.}
+}
+\description{
+Adds a landing popup to the \code{teal} app. This popup will be shown when the app starts.
+The dialog must be closed by the app user to proceed to the main application.
+}
+\examples{
+app <- init(
+  data = teal_data(IRIS = iris, MTCARS = mtcars),
+  modules = modules(example_module())
+) |>
+  add_landing_modal(
+    title = "Welcome",
+    content = "This is a landing popup.",
+    buttons = modalButton("Accept")
+  )
+
+if (interactive()) {
+  shinyApp(app$ui, app$server)
+}
+}
diff --git a/man/init.Rd b/man/init.Rd
index 81366add0..f142e43b4 100644
--- a/man/init.Rd
+++ b/man/init.Rd
@@ -8,11 +8,10 @@ init(
   data,
   modules,
   filter = teal_slices(),
-  title = build_app_title(),
-  header = tags$p(),
-  footer = tags$p(),
-  id = lifecycle::deprecated(),
-  landing_popup = NULL
+  title = lifecycle::deprecated(),
+  header = lifecycle::deprecated(),
+  footer = lifecycle::deprecated(),
+  id = lifecycle::deprecated()
 )
 }
 \arguments{
@@ -28,24 +27,24 @@ more details.}
 \item{filter}{(\code{teal_slices}) Optionally,
 specifies the initial filter using \code{\link[=teal_slices]{teal_slices()}}.}
 
-\item{title}{(\code{shiny.tag} or \code{character(1)}) Optionally,
+\item{title}{(\code{shiny.tag} or \code{character(1)}) \ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} Optionally,
 the browser window title. Defaults to a title "teal app" with the icon of NEST.
 Can be created using the \code{build_app_title()} or
-by passing a valid \code{shiny.tag} which is a head tag with title and link tag.}
+by passing a valid \code{shiny.tag} which is a head tag with title and link tag.
+This parameter is deprecated. Use \code{modify_title()} on the teal app object instead.}
 
-\item{header}{(\code{shiny.tag} or \code{character(1)}) Optionally,
-the header of the app.}
+\item{header}{(\code{shiny.tag} or \code{character(1)}) \ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} Optionally,
+the header of the app.
+This parameter is deprecated. Use \code{modify_header()} on the teal app object instead.}
 
-\item{footer}{(\code{shiny.tag} or \code{character(1)}) Optionally,
-the footer of the app.}
+\item{footer}{(\code{shiny.tag} or \code{character(1)}) \ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} Optionally,
+the footer of the app.
+This parameter is deprecated. Use \code{modify_footer()} on the teal app object instead.}
 
 \item{id}{\ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} (\code{character}) Optionally,
 a string specifying the \code{shiny} module id in cases it is used as a \code{shiny} module
 rather than a standalone \code{shiny} app. This is a legacy feature. Deprecated since v0.15.3
 please use \code{\link[=ui_teal]{ui_teal()}} and \code{\link[=srv_teal]{srv_teal()}} instead.}
-
-\item{landing_popup}{(\code{teal_module_landing}) Optionally,
-a \code{landing_popup_module} to show up as soon as the teal app is initialized.}
 }
 \value{
 Named list containing server and UI functions.
@@ -98,10 +97,7 @@ app <- init(
       `Iris Sepal.Length histogram` = "new_iris Species",
       global_filters = "new_mtcars cyl"
     )
-  ),
-  title = "App title",
-  header = tags$h1("Sample App"),
-  footer = tags$p("Sample footer")
+  )
 )
 if (interactive()) {
   shinyApp(app$ui, app$server)
diff --git a/man/landing_popup_module.Rd b/man/landing_popup_module.Rd
index af7c79c72..304c2cedb 100644
--- a/man/landing_popup_module.Rd
+++ b/man/landing_popup_module.Rd
@@ -25,49 +25,9 @@ Passed to \code{...} of \code{shiny::modalDialog}. See examples.}
 A \code{teal_module} (extended with \code{teal_landing_module} class) to be used in \code{teal} applications.
 }
 \description{
-Creates a landing welcome popup for \code{teal} applications.
+\ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} Creates a landing welcome popup for \code{teal} applications.
 
 This module is used to display a popup dialog when the application starts.
 The dialog blocks access to the application and must be closed with a button before the application can be viewed.
-}
-\examples{
-app1 <- init(
-  data = teal_data(iris = iris),
-  modules = modules(
-    example_module()
-  ),
-  landing_popup = landing_popup_module(
-    content = "A place for the welcome message or a disclaimer statement.",
-    buttons = modalButton("Proceed")
-  )
-)
-if (interactive()) {
-  shinyApp(app1$ui, app1$server)
-}
-
-app2 <- init(
-  data = teal_data(iris = iris),
-  modules = modules(
-    example_module()
-  ),
-  landing_popup = landing_popup_module(
-    title = "Welcome",
-    content = tags$b(
-      "A place for the welcome message or a disclaimer statement.",
-      style = "color: red;"
-    ),
-    buttons = tagList(
-      modalButton("Proceed"),
-      actionButton("read", "Read more",
-        onclick = "window.open('http://google.com', '_blank')"
-      ),
-      actionButton("close", "Reject", onclick = "window.close()")
-    )
-  )
-)
-
-if (interactive()) {
-  shinyApp(app2$ui, app2$server)
-}
-
+This function is deprecated, please use \code{add_landing_modal()} on the teal app object instead.
 }
diff --git a/man/module_bookmark_manager.Rd b/man/module_bookmark_manager.Rd
index 1e6dc7ae8..b76af700b 100644
--- a/man/module_bookmark_manager.Rd
+++ b/man/module_bookmark_manager.Rd
@@ -22,9 +22,8 @@ need_bookmarking(modules)
 \arguments{
 \item{id}{(\code{character(1)}) \code{shiny} module instance id.}
 
-\item{modules}{(\code{list} or \code{teal_modules} or \code{teal_module})
-Nested list of \code{teal_modules} or \code{teal_module} objects or a single
-\code{teal_modules} or \code{teal_module} object. These are the specific output modules which
+\item{modules}{(\code{teal_modules})
+\code{teal_modules} object. These are the specific output modules which
 will be displayed in the \code{teal} application. See \code{\link[=modules]{modules()}} and \code{\link[=module]{module()}} for
 more details.}
 }
diff --git a/man/module_filter_data.Rd b/man/module_filter_data.Rd
index 39d908999..0498657c3 100644
--- a/man/module_filter_data.Rd
+++ b/man/module_filter_data.Rd
@@ -30,9 +30,8 @@ which implies in filter-panel to be "global". When \code{NULL} then filter-panel
 
 \item{data}{(\code{reactive} returning \code{teal_data})}
 
-\item{modules}{(\code{list} or \code{teal_modules} or \code{teal_module})
-Nested list of \code{teal_modules} or \code{teal_module} objects or a single
-\code{teal_modules} or \code{teal_module} object. These are the specific output modules which
+\item{modules}{(\code{teal_modules})
+\code{teal_modules} object. These are the specific output modules which
 will be displayed in the \code{teal} application. See \code{\link[=modules]{modules()}} and \code{\link[=module]{module()}} for
 more details.}
 }
diff --git a/man/module_session_info.Rd b/man/module_session_info.Rd
new file mode 100644
index 000000000..1c15bd28b
--- /dev/null
+++ b/man/module_session_info.Rd
@@ -0,0 +1,35 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/module_session_info.R
+\name{module_session_info}
+\alias{module_session_info}
+\alias{ui_session_info}
+\alias{srv_session_info}
+\title{\code{teal} user session info module}
+\usage{
+ui_session_info(id)
+
+srv_session_info(id)
+}
+\arguments{
+\item{id}{(\code{character(1)}) \code{shiny} module instance id.}
+}
+\value{
+\code{NULL} invisibly
+}
+\description{
+Module to display the user session info popup and to download a lockfile.
+}
+\examples{
+ui <- fluidPage(
+  ui_session_info("session_info")
+)
+
+server <- function(input, output, session) {
+  srv_session_info("session_info")
+}
+
+if (interactive()) {
+  shinyApp(ui, server)
+}
+
+}
diff --git a/man/module_teal.Rd b/man/module_teal.Rd
index a3c13d295..c6ba7b206 100644
--- a/man/module_teal.Rd
+++ b/man/module_teal.Rd
@@ -6,36 +6,18 @@
 \alias{srv_teal}
 \title{\code{teal} main module}
 \usage{
-ui_teal(
-  id,
-  modules,
-  title = build_app_title(),
-  header = tags$p(),
-  footer = tags$p()
-)
+ui_teal(id, modules)
 
 srv_teal(id, data, modules, filter = teal_slices())
 }
 \arguments{
 \item{id}{(\code{character(1)}) \code{shiny} module instance id.}
 
-\item{modules}{(\code{list} or \code{teal_modules} or \code{teal_module})
-Nested list of \code{teal_modules} or \code{teal_module} objects or a single
-\code{teal_modules} or \code{teal_module} object. These are the specific output modules which
+\item{modules}{(\code{teal_modules})
+\code{teal_modules} object. These are the specific output modules which
 will be displayed in the \code{teal} application. See \code{\link[=modules]{modules()}} and \code{\link[=module]{module()}} for
 more details.}
 
-\item{title}{(\code{shiny.tag} or \code{character(1)}) Optionally,
-the browser window title. Defaults to a title "teal app" with the icon of NEST.
-Can be created using the \code{build_app_title()} or
-by passing a valid \code{shiny.tag} which is a head tag with title and link tag.}
-
-\item{header}{(\code{shiny.tag} or \code{character(1)}) Optionally,
-the header of the app.}
-
-\item{footer}{(\code{shiny.tag} or \code{character(1)}) Optionally,
-the footer of the app.}
-
 \item{data}{(\code{teal_data}, \code{teal_data_module}, or \code{reactive} returning \code{teal_data})
 The data which application will depend on.}
 
@@ -47,11 +29,13 @@ specifies the initial filter using \code{\link[=teal_slices]{teal_slices()}}.}
 }
 \description{
 \ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#stable}{\figure{lifecycle-stable.svg}{options: alt='[Stable]'}}}{\strong{[Stable]}}
-Module to create a \code{teal} app. This module can be called directly instead of \code{\link[=init]{init()}} and
-included in your custom application. Please note that \code{\link[=init]{init()}} adds \code{reporter_previewer_module}
-automatically, which is not a case when calling \code{ui/srv_teal} directly.
+Module to create a \code{teal} app as a Shiny Module.
 }
 \details{
+This module can be used instead of \code{\link[=init]{init()}} in custom Shiny applications. Unlike \code{\link[=init]{init()}}, it doesn't
+automatically include \code{reporter_previewer_module}, \code{module_session_info}, or UI components like
+\code{header}, \code{footer}, and \code{title} which can be added separately in the Shiny app consuming this module.
+
 Module is responsible for creating the main \code{shiny} app layout and initializing all the necessary
 components. This module establishes reactive connection between the input \code{data} and every other
 component in the app. Reactive change of the \code{data} passed as an argument, reloads the app and
diff --git a/man/module_teal_module.Rd b/man/module_teal_module.Rd
index abf84d928..c12912dbd 100644
--- a/man/module_teal_module.Rd
+++ b/man/module_teal_module.Rd
@@ -67,9 +67,8 @@ srv_teal_module(
 \arguments{
 \item{id}{(\code{character(1)}) \code{shiny} module instance id.}
 
-\item{modules}{(\code{list} or \code{teal_modules} or \code{teal_module})
-Nested list of \code{teal_modules} or \code{teal_module} objects or a single
-\code{teal_modules} or \code{teal_module} object. These are the specific output modules which
+\item{modules}{(\code{teal_modules})
+\code{teal_modules} object. These are the specific output modules which
 will be displayed in the \code{teal} application. See \code{\link[=modules]{modules()}} and \code{\link[=module]{module()}} for
 more details.}
 
diff --git a/man/module_teal_with_splash.Rd b/man/module_teal_with_splash.Rd
index 1bad555d6..26f4a5e6f 100644
--- a/man/module_teal_with_splash.Rd
+++ b/man/module_teal_with_splash.Rd
@@ -9,6 +9,7 @@
 ui_teal_with_splash(
   id,
   data,
+  modules,
   title = build_app_title(),
   header = tags$p(),
   footer = tags$p()
@@ -22,22 +23,24 @@ srv_teal_with_splash(id, data, modules, filter = teal_slices())
 \item{data}{(\code{teal_data}, \code{teal_data_module}, or \code{reactive} returning \code{teal_data})
 The data which application will depend on.}
 
-\item{title}{(\code{shiny.tag} or \code{character(1)}) Optionally,
+\item{modules}{(\code{teal_modules})
+\code{teal_modules} object. These are the specific output modules which
+will be displayed in the \code{teal} application. See \code{\link[=modules]{modules()}} and \code{\link[=module]{module()}} for
+more details.}
+
+\item{title}{(\code{shiny.tag} or \code{character(1)}) \ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} Optionally,
 the browser window title. Defaults to a title "teal app" with the icon of NEST.
 Can be created using the \code{build_app_title()} or
-by passing a valid \code{shiny.tag} which is a head tag with title and link tag.}
+by passing a valid \code{shiny.tag} which is a head tag with title and link tag.
+This parameter is deprecated. Use \code{modify_title()} on the teal app object instead.}
 
-\item{header}{(\code{shiny.tag} or \code{character(1)}) Optionally,
-the header of the app.}
+\item{header}{(\code{shiny.tag} or \code{character(1)}) \ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} Optionally,
+the header of the app.
+This parameter is deprecated. Use \code{modify_header()} on the teal app object instead.}
 
-\item{footer}{(\code{shiny.tag} or \code{character(1)}) Optionally,
-the footer of the app.}
-
-\item{modules}{(\code{list} or \code{teal_modules} or \code{teal_module})
-Nested list of \code{teal_modules} or \code{teal_module} objects or a single
-\code{teal_modules} or \code{teal_module} object. These are the specific output modules which
-will be displayed in the \code{teal} application. See \code{\link[=modules]{modules()}} and \code{\link[=module]{module()}} for
-more details.}
+\item{footer}{(\code{shiny.tag} or \code{character(1)}) \ifelse{html}{\href{https://lifecycle.r-lib.org/articles/stages.html#deprecated}{\figure{lifecycle-deprecated.svg}{options: alt='[Deprecated]'}}}{\strong{[Deprecated]}} Optionally,
+the footer of the app.
+This parameter is deprecated. Use \code{modify_footer()} on the teal app object instead.}
 
 \item{filter}{(\code{teal_slices}) Optionally,
 specifies the initial filter using \code{\link[=teal_slices]{teal_slices()}}.}
diff --git a/man/teal_extend_server.Rd b/man/teal_extend_server.Rd
new file mode 100644
index 000000000..365b7d27e
--- /dev/null
+++ b/man/teal_extend_server.Rd
@@ -0,0 +1,20 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/teal_modifiers.R
+\name{teal_extend_server}
+\alias{teal_extend_server}
+\title{Add a Custom Server Logic to \code{teal} Application}
+\usage{
+teal_extend_server(x, custom_server, module_id = character(0))
+}
+\arguments{
+\item{x}{(\code{teal_app}) A \code{teal_app} object created using the \code{init} function.}
+
+\item{custom_server}{(\verb{function(input, output, session)} or \verb{function(id, ...)})
+The custom server function or server module to set.}
+
+\item{module_id}{(\code{character(1)}) The ID of the module when a module server function is passed.}
+}
+\description{
+Adds a custom server function to the \code{teal} app. This function can define additional server logic.
+}
+\keyword{internal}
diff --git a/man/teal_modifiers.Rd b/man/teal_modifiers.Rd
new file mode 100644
index 000000000..7bafef0b4
--- /dev/null
+++ b/man/teal_modifiers.Rd
@@ -0,0 +1,63 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/teal_modifiers.R
+\name{teal_modifiers}
+\alias{teal_modifiers}
+\alias{modify_title}
+\alias{modify_header}
+\alias{modify_footer}
+\title{Replace UI Elements in \code{teal} UI objects}
+\usage{
+modify_title(
+  x,
+  title = "teal app",
+  favicon =
+    "https://raw.githubusercontent.com/insightsengineering/hex-stickers/main/PNG/nest.png"
+)
+
+modify_header(x, element = tags$p())
+
+modify_footer(x, element = tags$p())
+}
+\arguments{
+\item{x}{(\code{teal_app}) A \code{teal_app} object created using the \code{init} function.}
+
+\item{title}{(\code{shiny.tag} or \code{character(1)}) The new title to be used.}
+
+\item{favicon}{(\code{character}) The path for the icon for the title.
+The image/icon path can be remote or the static path accessible by \code{shiny}, like the \verb{www/}}
+
+\item{element}{Replacement UI element (shiny tag or HTML)}
+}
+\description{
+Replace UI Elements in \code{teal} UI objects
+}
+\examples{
+app <- init(
+  data = teal_data(IRIS = iris, MTCARS = mtcars),
+  modules = modules(example_module())
+) |>
+  modify_title(title = "Custom title")
+
+if (interactive()) {
+  shinyApp(app$ui, app$server)
+}
+app <- init(
+  data = teal_data(IRIS = iris),
+  modules = modules(example_module())
+) |>
+  modify_header(element = tags$div(h3("Custom header")))
+
+if (interactive()) {
+  shinyApp(app$ui, app$server)
+}
+app <- init(
+  data = teal_data(IRIS = iris),
+  modules = modules(example_module())
+) |>
+  modify_footer(element = "Custom footer")
+
+if (interactive()) {
+  shinyApp(app$ui, app$server)
+}
+}
+\keyword{internal}
diff --git a/tests/testthat/test-module_session_info.R b/tests/testthat/test-module_session_info.R
new file mode 100644
index 000000000..bff7f092e
--- /dev/null
+++ b/tests/testthat/test-module_session_info.R
@@ -0,0 +1,45 @@
+testthat::describe("srv_session_info lockfile", {
+  testthat::it(paste0(
+    "creation process is invoked for teal.lockfile.mode = \"enabled\" ",
+    "and snapshot is copied to teal_app.lock and removed after session ended"
+  ), {
+    testthat::skip_if_not_installed("mirai")
+    testthat::skip_if_not_installed("renv")
+    withr::with_options(
+      list(teal.lockfile.mode = "enabled"),
+      {
+        renv_filename <- "teal_app.lock"
+        shiny::testServer(
+          app = srv_session_info,
+          args = list(id = "test"),
+          expr = {
+            iter <- 1
+            while (!file.exists(renv_filename) && iter <= 1000) {
+              Sys.sleep(0.5)
+              iter <- iter + 1 # max wait time is 500 seconds
+            }
+            testthat::expect_true(file.exists(renv_filename))
+          }
+        )
+        testthat::expect_false(file.exists(renv_filename))
+      }
+    )
+  })
+  testthat::it("creation process is not invoked for teal.lockfile.mode = \"disabled\"", {
+    testthat::skip_if_not_installed("mirai")
+    testthat::skip_if_not_installed("renv")
+    withr::with_options(
+      list(teal.lockfile.mode = "disabled"),
+      {
+        renv_filename <- "teal_app.lock"
+        shiny::testServer(
+          app = srv_session_info,
+          args = list(id = "test"),
+          expr = {
+            testthat::expect_false(file.exists(renv_filename))
+          }
+        )
+      }
+    )
+  })
+})
diff --git a/tests/testthat/test-module_teal.R b/tests/testthat/test-module_teal.R
index 3a48c5895..a25eaec54 100644
--- a/tests/testthat/test-module_teal.R
+++ b/tests/testthat/test-module_teal.R
@@ -65,60 +65,6 @@ transform_list <<- list(
   )
 )
 
-testthat::describe("srv_teal lockfile", {
-  testthat::it(paste0(
-    "creation process is invoked for teal.lockfile.mode = \"enabled\" ",
-    "and snapshot is copied to teal_app.lock and removed after session ended"
-  ), {
-    testthat::skip_if_not_installed("mirai")
-    testthat::skip_if_not_installed("renv")
-    withr::with_options(
-      list(teal.lockfile.mode = "enabled"),
-      {
-        renv_filename <- "teal_app.lock"
-        shiny::testServer(
-          app = srv_teal,
-          args = list(
-            id = "test",
-            data = teal.data::teal_data(iris = iris),
-            modules = modules(example_module())
-          ),
-          expr = {
-            iter <- 1
-            while (!file.exists(renv_filename) && iter <= 1000) {
-              Sys.sleep(0.5)
-              iter <- iter + 1 # max wait time is 500 seconds
-            }
-            testthat::expect_true(file.exists(renv_filename))
-          }
-        )
-        testthat::expect_false(file.exists(renv_filename))
-      }
-    )
-  })
-  testthat::it("creation process is not invoked for teal.lockfile.mode = \"disabled\"", {
-    testthat::skip_if_not_installed("mirai")
-    testthat::skip_if_not_installed("renv")
-    withr::with_options(
-      list(teal.lockfile.mode = "disabled"),
-      {
-        renv_filename <- "teal_app.lock"
-        shiny::testServer(
-          app = srv_teal,
-          args = list(
-            id = "test",
-            data = teal.data::teal_data(iris = iris),
-            modules = modules(example_module())
-          ),
-          expr = {
-            testthat::expect_false(file.exists(renv_filename))
-          }
-        )
-      }
-    )
-  })
-})
-
 testthat::describe("srv_teal arguments", {
   testthat::it("accepts data to be teal_data", {
     testthat::expect_no_error(
diff --git a/tests/testthat/test-shinytest2-init.R b/tests/testthat/test-shinytest2-init.R
index e0672e7e5..9e0d6d436 100644
--- a/tests/testthat/test-shinytest2-init.R
+++ b/tests/testthat/test-shinytest2-init.R
@@ -19,7 +19,7 @@ testthat::test_that("e2e: teal app initializes with sessionInfo modal", {
   )
 
   # Check if button exists.
-  button_selector <- "#teal-sessionInfo-button"
+  button_selector <- "#teal-footer-session_info-sessionInfo-button"
   testthat::expect_equal(
     app$get_text(button_selector),
     "Session Info"
@@ -37,7 +37,7 @@ testthat::test_that("e2e: teal app initializes with sessionInfo modal", {
   testthat::expect_setequal(
     testthat::expect_length(
       app$get_text(
-        "#shiny-modal [id^='teal-sessionInfo-copy_button']"
+        "#shiny-modal [id^='teal-footer-session_info-sessionInfo-copy_button']"
       ),
       2
     ),
@@ -53,7 +53,7 @@ testthat::test_that("e2e: teal app initializes with sessionInfo modal", {
   )
 
   # Check session info output.
-  session_info <- app$get_text("#teal-sessionInfo-verbatim_content")
+  session_info <- app$get_text("#teal-footer-session_info-sessionInfo-verbatim_content")
 
   testthat::expect_match(session_info, "R version", fixed = TRUE)
   testthat::expect_match(session_info, "attached base packages:", fixed = TRUE)
@@ -68,39 +68,36 @@ testthat::test_that("e2e: teal app initializes with sessionInfo modal", {
 
 testthat::test_that("e2e: init creates UI containing specified title, favicon, header and footer", {
   skip_if_too_deep(5)
-  app_title <- "Custom Teal App Title"
-  app_favicon <- "https://raw.githubusercontent.com/insightsengineering/hex-stickers/main/PNG/teal.png"
-  app_header <- "Custom Teal App Header"
-  app_footer <- "Custom Teal App Footer"
   app <- TealAppDriver$new(
     data = simple_teal_data(),
     modules = example_module(label = "Example Module"),
-    title = build_app_title(
-      app_title,
-      app_favicon
+    title_args = list(
+      title = "Custom Teal App Title",
+      something_else = "asdfsdf",
+      favicon = "https://raw.githubusercontent.com/insightsengineering/hex-stickers/main/PNG/teal.png"
     ),
-    header = app_header,
-    footer = app_footer
+    header = "Custom Teal App Header",
+    footer = "Custom Teal App Footer"
   )
 
   testthat::expect_equal(
     app$get_text("head > title")[1],
-    app_title
+    "Custom Teal App Title"
   )
   testthat::expect_equal(
     rvest::html_attr(
       rvest::html_elements(app$get_html_rvest("head > link[rel='icon']"), "link"),
       "href"
     ),
-    app_favicon
+    "https://raw.githubusercontent.com/insightsengineering/hex-stickers/main/PNG/teal.png"
   )
   testthat::expect_match(
     app$get_text("header"),
-    app_header
+    "Custom Teal App Header"
   )
   testthat::expect_match(
     app$get_text("footer"),
-    app_footer
+    "Custom Teal App Footer"
   )
   app$stop()
 })
diff --git a/tests/testthat/test-shinytest2-landing_popup.R b/tests/testthat/test-shinytest2-landing_popup.R
index d2e8ba309..96c759718 100644
--- a/tests/testthat/test-shinytest2-landing_popup.R
+++ b/tests/testthat/test-shinytest2-landing_popup.R
@@ -8,7 +8,7 @@ testthat::test_that("e2e: teal app with landing_popup_module initializes with no
     modules = modules(
       example_module()
     ),
-    landing_popup = landing_popup_module(
+    landing_popup_args = list(
       title = "Welcome",
       content = tags$b("A welcome message!", style = "color: red;")
     )
@@ -28,7 +28,7 @@ testthat::test_that("e2e: app with default landing_popup_module creates modal co
     modules = modules(
       example_module()
     ),
-    landing_popup = landing_popup_module()
+    landing_popup_args = list()
   )
 
   testthat::expect_equal(
@@ -46,7 +46,7 @@ testthat::test_that("e2e: when default landing_popup_module is closed, it shows
     modules = modules(
       example_module()
     ),
-    landing_popup = landing_popup_module()
+    landing_popup_args = list()
   )
 
   # Button is clicked.
@@ -65,77 +65,64 @@ testthat::test_that(
   "e2e: app with customized landing_popup_module creates modal containing specified title, content and buttons",
   {
     skip_if_too_deep(5)
-    phash <- function(text) paste0("#", text)
-
-    modal_title <- "Custom Landing Popup Module Title"
-    modal_content_message <- "A welcome message!"
-    modal_content <- tags$b(modal_content_message, style = "color: red;")
-
-    modal_btns <- list(
-      go = list(text = "Proceed"),
-      more = list(text = "Read more", onclick = "window.open('http://google.com', '_blank')", id = "read"),
-      reject = list(text = "Reject", onclick = "window.close()", id = "close")
-    )
-    modal_buttons <-
-      tagList(
-        shiny::modalButton(modal_btns$go$text),
-        shiny::actionButton(
-          modal_btns$more$id,
-          label = modal_btns$more$text,
-          onclick = modal_btns$more$onclick
-        ),
-        shiny::actionButton(
-          modal_btns$reject$id,
-          label = modal_btns$reject$text,
-          onclick = modal_btns$reject$onclick
-        )
-      )
 
     app <- TealAppDriver$new(
       data = simple_teal_data(),
       modules = modules(
         example_module()
       ),
-      landing_popup = landing_popup_module(
-        title = modal_title,
-        content = modal_content,
-        buttons = modal_buttons
+      landing_popup_args = list(
+        title = "Custom Landing Popup Module Title",
+        content = tags$b("A welcome message!", style = "color: red;"),
+        footer = tagList(
+          shiny::modalButton("Proceed"),
+          shiny::actionButton(
+            "read",
+            label = "Read more",
+            onclick = "window.open('http://google.com', '_blank')"
+          ),
+          shiny::actionButton(
+            "close",
+            label = "Reject",
+            onclick = "window.close()"
+          )
+        )
       )
     )
 
     testthat::expect_equal(
       app$get_text(".modal-title"),
-      modal_title
+      "Custom Landing Popup Module Title"
     )
 
     testthat::expect_equal(
       trimws(app$get_text(".modal-body")),
-      modal_content_message
+      "A welcome message!"
     )
 
     testthat::expect_equal(
       app$get_text(".btn-default:nth-child(1)"),
-      modal_btns$go$text
+      "Proceed"
     )
 
     testthat::expect_equal(
-      app$get_text(phash(modal_btns$more$id)),
-      modal_btns$more$text
+      app$get_text("#read"),
+      "Read more"
     )
 
     testthat::expect_equal(
-      app$get_attr(phash(modal_btns$more$id), "onclick"),
-      modal_btns$more$onclick
+      app$get_attr("#read", "onclick"),
+      "window.open('http://google.com', '_blank')"
     )
 
     testthat::expect_equal(
-      app$get_text(phash(modal_btns$reject$id)),
-      modal_btns$reject$text
+      app$get_text("#close"),
+      "Reject"
     )
 
     testthat::expect_equal(
-      app$get_attr(phash(modal_btns$reject$id), "onclick"),
-      modal_btns$reject$onclick
+      app$get_attr("#close", "onclick"),
+      "window.close()"
     )
 
     app$stop()
@@ -144,20 +131,19 @@ testthat::test_that(
 
 testthat::test_that("e2e: when customized button in landing_popup_module is clicked, it redirects to a certain page", {
   skip_if_too_deep(5)
-  onclick_text <- "window.open('http://google.com', '_blank')"
   app <- TealAppDriver$new(
     data = simple_teal_data(),
     modules = modules(
       example_module()
     ),
-    landing_popup = landing_popup_module(
-      buttons = actionButton("read", "Read more", onclick = onclick_text)
+    landing_popup_args = list(
+      footer = actionButton("read", "Read more", onclick = "window.open('http://google.com', '_blank')")
     )
   )
 
   testthat::expect_equal(
     app$get_attr("#read", "onclick"),
-    onclick_text
+    "window.open('http://google.com', '_blank')"
   )
 
   app$stop()
diff --git a/vignettes/adding-support-for-reporting.Rmd b/vignettes/adding-support-for-reporting.Rmd
index 9c3730610..9ba72d496 100644
--- a/vignettes/adding-support-for-reporting.Rmd
+++ b/vignettes/adding-support-for-reporting.Rmd
@@ -355,9 +355,9 @@ app <- init(
     example_reporter_module(label = "with Reporter"),
     my_module(label = "without Reporter")
   ),
-  filter = teal_slices(teal_slice(dataname = "AIR", varname = "Temp", selected = c(72, 85))),
-  header = "Example teal app with reporter"
-)
+  filter = teal_slices(teal_slice(dataname = "AIR", varname = "Temp", selected = c(72, 85)))
+) |>
+  modify_header("Example teal app with reporter")
 
 if (interactive()) shinyApp(app$ui, app$server)
 ```
diff --git a/vignettes/bootstrap-themes-in-teal.Rmd b/vignettes/bootstrap-themes-in-teal.Rmd
index 8ea255e4c..3812e1a76 100644
--- a/vignettes/bootstrap-themes-in-teal.Rmd
+++ b/vignettes/bootstrap-themes-in-teal.Rmd
@@ -105,13 +105,12 @@ app <- init(
   data = teal_data(IRIS = iris), # nolint: line_length.
   filter = teal_slices(teal_slice("IRIS", "Sepal.Length", selected = c(5, 7))),
   modules = modules(example_module(), example_module()),
-  header = "My first teal application"
 )
 
 bslib::run_with_themer(shinyApp(app$ui, app$server))
 ```
 
-This gives us the following.
+This gives us a `Theme Customizer` similar to what is shown below.
 
 <img src="images/bs-launch.png" style="width: 100%;"/>
 
diff --git a/vignettes/getting-started-with-teal.Rmd b/vignettes/getting-started-with-teal.Rmd
index 342c7de05..921505cf9 100644
--- a/vignettes/getting-started-with-teal.Rmd
+++ b/vignettes/getting-started-with-teal.Rmd
@@ -40,11 +40,11 @@ app <- init(
   ),
   filter = teal_slices(
     teal_slice(dataname = "IRIS", varname = "Species", selected = "setosa")
-  ),
-  title = build_app_title(title = "My first teal app"),
-  header = h3("My first teal application"),
-  footer = tags$div(a("Powered by teal", href = "https://insightsengineering.github.io/teal/latest-tag/"))
-)
+  )
+) |>
+  modify_title("My first teal application") |>
+  modify_header(h3("My first teal application")) |>
+  modify_footer(tags$div(a("Powered by teal", href = "https://insightsengineering.github.io/teal/latest-tag/")))
 
 if (interactive()) {
   shinyApp(app$ui, app$server)