Dear Sammie Eskowitz,
Good day!!
Apologies for the inconvenience caused and please don’t worry, let’s work together on your concern and move towards a resolution path.
As per the description shared, I would like to confirm whether you are encountering the following prompt when you try to edit the Word document:
If my understanding is correct, I would like to let you know that the most possible cause of the problem is caused due to the restriction applied on the Word document:
Open the problematic Word document> Review tab> Protect> Restrict Editing> Stop Protection> Enter the password to unprotect it.

However, if it’s didn’t resolve your issue, we are sorry and I would like to request you check the all possible cause and suggestions for the error message you are encountering in the following discussion: Microsoft Word message: "You can't make this change because this - Microsoft Community
If none of them works, we are sorry and I would like to confirm the following scenarios which will help us to better understand and guide you further:
- Word app Account page: Open the Word document> File> Account> Take a screenshot and share it with us.
- Does the problem happens with the specific Word document or all Word documents including the new ones?
- If possible, please share the sample problematic Word document with us, where we can test it at our end and share the test results with you. You can upload the sample document to the cloud location and share the link with us.
Our sincere apologies for not resolving the problem is first reply but answers to above queries will help us to better understand your situation and guide you in the right direction.
Appreciate your patience and understanding. Have a great day!!
Best Regards,
Sophia