For people lacking suitable identification documents and who are unable to obtain them, California allows identity to be established on the basis of either one credible witness (if that witness is personally known also to the notary), or two credible witnesses whose identities are confirmed through the same identify documents used for signers. (See What Types of ID May a Notary Accept?)
Under oath, each credible witness must swear or affirm under penalty of perjury that each of the following items is true: The individual appearing before the notary public as the signer of the document is the person named in the document; The credible witness personally knows the signer; The credible witness reasonably believes that the circumstances of the signer are such that it would be very difficult or impossible for the signer to obtain another form of identification; The signer does not possess any of the identification documents authorized by law to establish the signer’s identity; and The credible witness does not have a financial interest and is not named in the document to be signed.
The nature of the document being executed may exclude direct family members from being credible witnesses. Please be patient with the notary when asked questions about the document and the relationships of the witnesses to the signer. Inappropriate witnesses could severely complicate if not negate the validity of the document.