Hi,
What is the detailed version of Word you are using? (Open Word, create a blank document, click
File >
Account to check Office product information)
Did you use the controls on
Developer Tab to create a fillable form? What are the controls you have inserted into document and want to edit?

Did you edit these controls under Design Mode?
Does the problem only occur when editing this file? Create a blank document and insert this form, will there be editing problems?
Where is this document from, and is it created by someone else?
As far as I know, it may be not easy to edit some Legacy Forms and ActiveX controls.
If you have any question about Office, please feel free to let me know.
Best Regards,
Herb Gu
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