Based on your description, I have some questions as below.
-What’s the version of your Office?
You could check it in File>Account>Product Information.
-Can you sign in OneDrive online successfully?
-How did you save files to OneDrive?
Did you save through File>Save As?
> It says that I am signed it when I go to my account through Microsoft word
<< Where are you signed in? User Information or Connected Services?
-Can you save files to other locations successfully?
Please give a screenshot of the message which says your email is not able to be used.
Any updates, please let me know.
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