I had two versions of some text and wanted to compare them using Word, so it would give the same annotation as if I had had 'track changes' turned on.
I tried this initially, but got a strange output from Word where it showed both versions of the text beside each other. After some fiddling, this is what worked:
(i) Paste one (the older) version of the text in one Word document. Accept all changes in the document. Save as 'oldversion'.
(ii) Paste the second (the newer) version of the text in a second Word document. Accept all changes in the document. Save as 'newversion'.
(iii) Quit Word and just one the one that is the 'newversion'.
(iv) Go to Tools -> Compare docs, and click on the down-arrow symbol to show all options, and select to show the changes in the newversion document.