What is the essential difference between an acknowledgment and a jurat?

An acknowledgment and a jurat are the two most common notarial acts, and they serve different purposes. In an acknowledgment, the signer appears before the notary and acknowledges that they signed the document willingly for its stated purpose; the signer may have signed it beforehand. In a jurat, the signer swears or affirms (under oath) that the contents of the document are true, and the signer must sign the document in the notary's presence. Both require the notary to verify the signer's identity. Knowing which act a document calls for — and the different requirements — is fundamental notary knowledge.