Signatures actually shouldn't be part of the same pdf document, since once you sign it you can't check that its the same document as before (unless you use eg. pdf-diff, related to #30).
Instead, signatures should probably be on some separate document that just contains the hash of the contract pdf. For electronic signatures this is possible by signing a contract that refers to the hash of the actual contract. For digital signatures, this is of course native.
Signatures actually shouldn't be part of the same pdf document, since once you sign it you can't check that its the same document as before (unless you use eg. pdf-diff, related to #30).
Instead, signatures should probably be on some separate document that just contains the hash of the contract pdf. For electronic signatures this is possible by signing a contract that refers to the hash of the actual contract. For digital signatures, this is of course native.