Acknowledgments, Proofs and Certificates
What an acknowledgment certifies
The signer personally appears, is identified, and states that he or she executed the instrument voluntarily for its stated purpose. The signer need not sign in the notary's presence - signing earlier is fine - but the appearance, identification, and acknowledgment must genuinely occur. Do not confuse this with a jurat: an acknowledgment contains no oath about truthfulness.
The certificate itself
Real Property Law §309-a supplies the statutory short form for an individual; §309-b covers a person acting as an officer of a corporation, a partner, an attorney in fact, or in another representative capacity, adding language that the individual executed the instrument in that capacity on behalf of the entity. Every certificate needs the venue (State of New York, County of ___ ), the date, the name of the person who appeared, whether the notary knew that person personally or identified them on satisfactory evidence, the acknowledgment language, and the notary's signature and stamp.
Proof of execution
When the signer cannot appear, a subscribing witness who watched the signer execute the instrument and who signed as a witness may appear and swear to those facts. The certificate then records the witness's testimony, not the maker's acknowledgment. A witness who only saw a finished document, or who signed without watching the execution, cannot supply proof.
Traps
Blank certificates, certificates completed before the person appears, and certificates naming someone who never appeared are all defective. A notary may not certify the acknowledgment of his or her own signature.
Example: "On the 4th day of June, 2024, before me, the undersigned, personally appeared Maria Ortiz, personally known to me ... and acknowledged ..." plus signature and stamp is complete; deleting the identification clause is not.