A customer came to the registry on Friday wanting to make "a notarized copy of [his] driver's license." He explained that he was applying for a mortgage and the lender required this.
The most common act by a Notary Public is to take an acknowledgement - that is, after identifying the person and witnessing his signature, then ascertaining whether the signature was a voluntary act. There are three other acts that can be accomplished by a Notary. Besides the Acknowledgement, there's the Jurat. With the Jurat, the person signing the document also swears or affirms that the contents of the document are true and accurate. The third notarial act is Signature Witnessing. In this case, the Notary affirms that the person who purports to have signed the document was in fact the person who signed it. The fourth Notarial Act is Copy Certification. Here, the Notary makes a copy of a document and then certifies that it is a "true, exact, complete, and unaltered copy" of the original.
For more details about these Notarial Acts and for examples of the verbiage used when affixing them to documents, see THIS pamphlet produced by the Secretary of the Commonwealth.