The notary will ask you for government-issued identification. They will carefully review the documentation for a few separate things:
Whether the identification appears authentic;
Signs of forgery;
Signs of alteration;
To confirm you are the person pictured in the identification; and
To confirm the type of identification offered meets the legal requirements.
Once they have reviewed your ID, they will witness you signing the document. The notary also signs the document and includes the date of signing. They will also have a notary stamp to affix to the document.