What does the check mark `Lock document after signing` do in Acrobat Reader?
Matthew Martinez 
I need to sign PDF documents with the Acrobat Reader DC (V19, Win10).
What consequences does the check mark Lock document after signing specifically have? This is what I checked/got so far (partly from the existing answers/comments), when you open it in various PDF readers (e.g. Adobe Reader, Foxit, etc.) which support digital signatures:
- It disables editing tools (e.g. annotation tool)
- It disables form fields
- It blocks additional signatures (if there should be multiple signatures on the document the first person not enable the lock)
This is, what I noticed so far and is included in the FAQ file which, unfortunately, the FAQs are rather unsubstantial.
Is it still possible to remove the signature if the signature if the document needs to be edited after it got signed (in case the unsigned file got lost)?
1 Answer
Adobe Edit a signed PDF | FAQsays this:
What if a PDF is locked after signing?
Occasionally, you or the signer may choose to lock the document after signing. In this case, the document becomes read-only and no further changes are allowed; even a signature can’t be added in the document. The Lock document after signing option is useful if you’re the last signer or the only one signer.
This option allows locking the document from further editing or signing after your signature is placed. Select this only if you are the last person to digitally sign this document, because it locks the document and all of the fields in it, making it totally read-only.
For removal of the signature, the same FAQ says this:
Can I edit a PDF that I signed?
If you’re the only one signer, you can remove the signature and then work on the document or edit the source document.
To remove your signature, right-click the signature and then choose Clear Signature.
