I just answered my own question, since I had the MS report in Word.
I was hoping I'd have to supply a password to edit it, which would be a somewhat reasonable level of security. But no; you just click "edit anyway." Duh.
I was hoping I'd have to supply a password to edit it, which would be a somewhat reasonable level of security. But no; you just click "edit anyway." Duh.
The best you can do is a digital signature[1], which proves that the document has not been tampered with. Of course, it's up to the recipient to ask for a signed document and to actually check if the signature is still present and accurate upon receipt. Otherwise, it's very trivial for a third-party to remove the signature and add their own edits.
[1]: https://support.microsoft.com/en-us/topic/add-or-remove-a-di...