The Acrobat user interface uses the term “Bookmarks” for a collection of document placeholders.  In the Acrobat user interface the Bookmarks are displayed in separate window pane located to the left side of the document window. Note: In the PDF Reference and ISO-32000; the term used is “Outlines”.

In PDF, an annotation is an item separate from the page content which is located in a layer above the page content.  For example, like a Post-It® note is located over the text of a page. Annotations can take many forms. The following is a list of the most common annotations used in PDF: Markup […]