Bookmark - Viable but Not Printed (and doesn't take up space)

When drafting documents (especially legal documents), I like to have internal notes with sections, so if I have another idea, I know where to put it so it is surrounded by similar themed ideas. For example, I may have a list of questions, one section of questions is directed at "VACATION TAKEN" and another section is directed at "INTERACTION WITH COWORKERS" It would be great if I had the ability to have internal notes on the document so I can find the sections easier. These notes would be visible, but would not print or take up any space on the page. Maybe even be able to use these notes to designate a beggining and an end of a section, and the section could have a slightly different background (or border) to see where the section ends and begins. Think "bookmarks" for internal reference.