I need more information in order to help you better.
Does this issue occur with a specific Word document or all Word documents?
Are there any error messages when trying to save the Word document?
Are you able to open, work and save other Office applications like Excel or PowerPoint?
Provide the required details to assist you.
This issue may occur due to several reasons. Let us start with opening Word in safe mode. To do that, follow the steps below.
Hold the Windows key and press R, type winword /safe (note there is a space betweenwinword and /).
If the application works fine safe mode, try disabling the add ins for the application and check the result.
Click the File tab.
Go to Options.
Clear all the options.