What information may be added to a notarial certificate as optional?

In the context of notarization, a notarial certificate can indeed include optional information that provides more context or clarity about the transaction but is not universally required for the certificate to be valid. Among the options presented, adding additional legal requirements or details falls into this category of optional information.

Including extra details can enhance the notarial certificate by providing specific information that may be relevant to the notarial act or by clarifying the transaction's purpose. This additional context can assist in fulfilling any special legal needs that might be pertinent to the situation beyond the basic requirements of the notarization itself.

On the other hand, the other options typically represent standard or required elements that are often necessary for a complete notarial certificate. For instance, a signer's address might be essential for identification purposes, and the notary's commission expiration date is usually mandated by law to ensure transparency regarding the notary's authority. Likewise, while witness signatures can be crucial for certain transactions, they are not automatically optional information within a notarial certificate. Thus, additional legal requirements or details are indeed the component that can be supplemented on a certificate as needed while retaining its primary validity.