Prohibited Acts, Conflicts of Interest, and Penalties
Conflicts you must refuse
A notary may not perform a notarial act on a record in which the notary is a signer, a party, or holds a direct beneficial interest, and the same bar generally reaches the notary's spouse. You cannot notarize your own signature or your own affidavit, you cannot notarize a deed you are buying or selling, and an officer of a company should not notarize that company's papers where the officer's interest is direct. The remedy is always the same: someone else performs the act.
Unauthorized practice of law
Explaining a document's legal effect, choosing which document a customer needs, drafting or completing legal text, or advising about the consequences of signing is the practice of law, not notarization. Related advertising restrictions mean you may not hold yourself out as a "notario publico" or under a non-English title implying legal authority without the required disclosures. You may explain what a notarial act is; you may not advise.
Other prohibited conduct
Notarizing without the signer present, using another person's seal, acting after expiration or suspension, backdating, and charging more than the statutory fee per act. Personal appearance is the backbone of the system; every shortcut around it is a violation.
Penalties
The Secretary of State may deny, suspend, revoke, or refuse to renew a commission and may impose civil penalties; certain violations are criminal misdemeanors carrying fines and possible jail time; the surety bond and civil liability expose the notary personally to an injured party.
Worked example
Your spouse asks you to notarize the deed transferring your jointly owned rental house. You are a grantor and the notary's spouse is a party - two independent grounds to refuse. Send the closing to another notary.