Viewing, comparing, and combining changes
We have seen how to use Track Changes, and how it can be very helpful when collaborating on a shared document with multiple authors. But think about this scenario – you have sent a document out for revision to multiple authors, and they have sent you revised versions of the document. Word gives us the tools we need to work with multiple versions of the same document, and we can also use Compare and Combine to compare two versions of a single document saved in OneDrive.
Documents saved to OneDrive versus documents saved locally
If the document you are working with has not been saved to OneDrive, only the Compare and Combine options will be present. Saving previous versions of documents is done automatically in OneDrive. Documents saved to your local computer will not save previous versions of the document.
To compare or combine two versions of a document, you must select the Review tab on the ribbon and go to the Compare section...