Hi Fahd,
Thank you for sharing your question. I get how annoying it is when stuff like the Document option and Vertical Alignment go haywire after you update, especially since you use Word to write books. Let’s sort this together.
Based on my knowledge, this kind of thing pops up after updates mess with Word for Mac. The Format > Document thing, where you set vertical alignment, might freeze up or vanish because of UI bugs or updates that didn't finish right. Microsoft knows about these kinds of issues in recent versions and suggests looking for updates or fixing the install.
Please follow these steps.
Fix or Reinstall Office: If updating doesn't do the trick, uninstall Office and reinstall it from Microsoft's site. This gets rid of any broken bits.
Find Vertical Alignment: Once Word is working, you can find vertical alignment under Format > Document > Layout tab. If the window still won't open, try clearing the app's settings or resetting Word.
Check macOS: Make sure your Mac is running the newest macOS version that Office 2021 supports, since older versions can mess with features
May I also ask, does this happen only in Word, or in other Office programs too? Also, do you see any messages about activating or licensing when you open Word? This will help figure out if it's an activation problem or just a UI bug.
I hope this answer is helpful, if you have any questions, feel free to reply.
Best Regards,
Noel