What happens to the file
The archive is unpacked, the document properties are blanked, the comment parts are removed, tracked insertions are accepted and tracked deletions are removed, editor names are cleared, and the whole thing is repacked. The result opens in Word normally with your text intact.
Why not just use Document Inspector
You should, when you have Word open. It is thorough and it is built in. This exists for the times you do not — on a phone, on someone else's machine, or when you have received a file and want to know what is in it before you open it in anything.
Check before you clean
The report is worth reading first. Seeing that a document you are about to forward contains eleven tracked deletions and a comment from a colleague is more useful than silently removing them.