Word has its own version control built in, which works pretty well. You can see all revisions, and step through and accept/reject. You can also do diff of two documents.
report.latest.2017_0713.new.with_additions.current.adamssversion.ready.lastchange.docx
And if you have 3 people collaborating, sooner or later someone makes edits to something besides HEAD and then there's a giant mess to sort out.