Those get inserted automatically if you cross-reference to the document, or
if you cut and paste from that document to another.

Hi Ricki,

Word sometimes does this if you copy text from one part of your document and insert it elsewhere in the same or another document,
especially if you paste the copied material as a link (eg via Edit|Paste Special). Cross-referencing, per se, has nothing to do with
it. There's no satisfactory explanation for why Word sometimes inserts these bookmarks when no linking is involved.

Cheers