What does digital signing have to do with identity? When you sign a document, or form, your X509 signing certificate is, in effect, representing you or your identity.
Being able to digitally sign on-line forms, with a legally binding signature, would avoid the time and expense of using paper forms, so why aren't we all doing it? The reason is that very few of us have high assurance X509 certificates.
However, with the availability of Verified Cloud Identities (VCId), digital signing of online forms can be made a practical reality. Using the claims from the VCId, a signing key pair can be created and used to sign with, creating a signature in a standard (e.g. PKCS#7) format.
A further enhancement to assist in non-repudiation of the signature is to incorporate into the signature a screen capture of the signed form, so preventing either the signer or the host from denying exactly what was being signed.