PDF documents usually include bookmarks in the navigation panel which act as a table of contents. A bookmark can be considered as a type of link with representative text, initially linking to a part or section of a PDF document that was in view when it was created. You can click an existing bookmark to a page view within current document, to another document, or to a web page.
You can add new bookmarks for PDF documents. For example, add a bookmark to mark a place in a document to which you want to return, or direct your readers’ attention where you want it.
You can set actions for bookmarks, such as opening a file or executing a menu item.
Note: A user can add bookmarks to a document only if the security settings allow it.