Signatory – Also known as a Signer. This is the recipient of the document who will be providing information upon signing. For example: their names, private history, or other personal information.
Why not just call it a signer, you ask? Well, "signer" is 2 syllables, and "signatory" is 4 syllables. Writing "signatory" beefs up our internal documentation quite a bit and some of us are paid by the character. But, if you must, you may refer to people who sign documents as "Signers."