How to incorporate Documentation into wordpress?

WordPress allows you to add help tabs which appear in your Dashboard and on each admin page.

$screen = get_current_screen();

$screen->add_help_tab( array( 

   'id' => $id,            //unique id for the tab
   'title' => $title,      //unique visible title for the tab
   'content' => $content,  //actual help text
   'callback' => $callback //optional function to callback

) );

APIGen or PHPDoc can help create your PHP documentation from your DockBlocks and render as HTML.

There are other various plugins like WP Help and Documentor that might help.

But it’s almost like you want a living style guide like this or this.

Your best bet is to stick with help tabs and link to your auto-generated pages elsewhere — or do your docs as a book.