Michelle makes an excellent point.
If the ONLY way that the freelancer has submitted the file to the client is through Upwork - and not using a known-dependable file transfer method such as email, Dropbox, FTP, etc...
Then the client does not actually know if the freelancer created a usable file or not.
Ideally, freelancers themselves would be aware of the limitations and problems inherent with transferring files via Upwork's tools... Ideally the freelancer would have sent the client a screenshot of the modified file, and sent the actual Word document via email/FTP/Dropbox/etc., and told the client what to expect.
But not every freelancer is sophisticated enough to do that.