While only one state — California — requires Notaries to record signers’ thumbprints for certain transactions, the NNA recommends that Notaries do not obtain a thumbprint unless required by state law.
Have your signer touch a standard inking device with his or her right thumb and then touch the journal page to leave a print. Imprinting the right thumb is standard practice for law enforcement use, and as a biometric identifier in official IDs, such as driver’s licenses.
If your journal does not include a specific space for a thumbprint, then use the space indicated for “Additional Information,” provided that the thumbprint does not cross any intersecting lines or cover preprinted words.