Notarial Acts & Their Differences
A New York notary may administer oaths and affirmations, take affidavits and depositions, take acknowledgments and proofs of deeds, and protest notes—but New York notably does NOT allow notaries to certify copies or solemnize marriages.
Acknowledgment vs. oath/affidavit
In an acknowledgment the signer appears and declares they executed the document; the notary confirms identity and completes the certificate. For an affidavit or deposition the notary administers an oath and the signer swears to the truth of the contents. New York notaries frequently take acknowledgments for real-property documents and administer oaths for affidavits—know which the document calls for.
Acts a New York notary may NOT do
A New York notary may not certify copies of documents (there is no notarial copy certification in NY), may not solemnize marriages, and may not give legal advice or prepare legal documents unless separately licensed. Certifying a 'true copy' is a common exam trap—New York notaries simply do not have that power.