Header 1

Header 2

Header 3

Header 4

Header 5

show with app
app.R
shinyApp(
  ui = tagList(
    shinythemes::themeSelector(),
    navbarPage(
      # theme = "cerulean",  # <--- To use a theme, uncomment this
      "shinythemes",
      tabPanel("Navbar 1",
        sidebarPanel(
          fileInput("file", "File input:"),
          textInput("txt", "Text input:", "general"),
          sliderInput("slider", "Slider input:", 1, 100, 30),
          tags$h5("Deafult actionButton:"),
          actionButton("action", "Search"),

          tags$h5("actionButton with CSS class:"),
          actionButton("action2", "Action button", class = "btn-primary")
        ),
        mainPanel(
          tabsetPanel(
            tabPanel("Tab 1",
              h4("Table"),
              tableOutput("table"),
              h4("Verbatim text output"),
              verbatimTextOutput("txtout"),
              h1("Header 1"),
              h2("Header 2"),
              h3("Header 3"),
              h4("Header 4"),
              h5("Header 5")
            ),
            tabPanel("Tab 2"),
            tabPanel("Tab 3")
          )
        )
      ),
      tabPanel("Navbar 2"),
      tabPanel("Navbar 3")
    )
  ),
  server = function(input, output) {
    output$txtout <- renderText({
      paste(input$txt, input$slider, format(input$date), sep = ", ")
    })
    output$table <- renderTable({
      head(cars, 4)
    })
  }
)