Which of the following is true about a notary's duties?

A notary’s primary duties revolve around witnessing signatures, administering oaths, and performing other notarial acts to ensure the authenticity of documents. The statement that notaries can witness signatures but cannot provide legal interpretations accurately captures the essence of a notary's role. Notaries are trained to verify identities, ensure that documents are signed voluntarily, and that the signers are of sound mind, but they do not have the authority to interpret legal documents or advise on legal matters. This is crucial for maintaining the impartiality and integrity of the notarial process, ensuring that the notary does not step into the role of a legal advisor, which could lead to potential conflicts of interest or liability.

In contrast, the other options introduce misconceptions about a notary's responsibilities. For example, notaries do not determine the legality of documents (which shifts their role into the realm of legal advice), are not required to perform notarial acts for free (as they may charge a fee regulated by the state), and cannot advise clients on how to fill out legal forms, which similarly falls outside their duties as neutral witnesses.