What it proves
A signed record carries three things: identity (who approved), time (when) and integrity (nothing changed after that moment). With ink, integrity is weak: a page can be swapped, a date written later. With an electronic signature the document's digest is bound inside the signature, and if a single character changes, verification fails.
Digest and verification
A short digest produced from the whole document is its fingerprint. Keeping that digest, without sharing the document, makes it possible to state later that "this document looked like this on that day". That is why an immutability record holds only the digest and never the document — personal data never leaves.
Reports produced by Optifora can be signed, are stored with their digest, and can be verified from a QR code.