How do you create bookmarks in acrobat xi pro?

There are many ways. Using the key combination of Control + B is one. One can also highlight some text and use the right mouse click to bring up the context menu and select "Create Bookmark", there is also the star on the bookmark navigation panel that can create a bookmark. If converting form Word one can also set he parameters for the Acrobat PDF Maker to create bookmarks from the structure of Word.

Ctrl+B.