What is a notary's main responsibility when notarizing a document?

A notary's primary responsibility when notarizing a document is to verify the identity of the signer. This critical step ensures that the individual signing the document is indeed who they claim to be, which helps to prevent fraud and protects the integrity of the notarization process. Notaries typically require the signer to present a valid form of identification, such as a driver's license or passport, and may also ask the signer to acknowledge their understanding of the document's content and their willingness to sign it.

The other options reflect misconceptions about the role of a notary. Filling in missing information or ensuring a document is completed in any form is not a responsibility of a notary; they must only notarize documents that are presented to them in their completed state. Additionally, notaries are not authorized to provide legal advice or interpret the contents of legal documents. Their function is purely to perform the act of notarization, which revolves around verifying identities and witnessing signatures.