What is a signature by mark?
When a person signs their signature by using a “mark” instead of their normal (original, usually longer) signature, this is considered a signature by mark.
David Thun from the National Notary Association says the following about what a signature by mark is, in this article titled “How to Handle A Signature BY Mark”
“A signature by mark is an alternative to writing a full signature. The signer instead makes a mark (such as an "X") or other symbols on the document. Under the laws of many states, a mark is considered a signature and is treated as such”
Does a signature by mark have the same legal effect as a normal signature?
Yes, the mark is legally binding and has the same effect/power as a signature of normal length or capacity. View UCC 3-401 for more information on this
Under what circumstances will I encounter this as a notary?
Common examples of when you will encounter a signer who is making their signature by mark;
A signer who has decreased mobility due to age, illness or an accident that reduced their mobility.
A signer in a nursing home who may need help signing but otherwise be mentally aware of what is going on
Important - As a notary, you must always be aware of the signer’s cognitive state. It is your responsibility as a notary (and a public servant) to ensure that the signer is aware of the situation they are in, and that they are aware of the purpose of document they are signing. If you do not feel like the signer is mentally aware enough to be cognitive of the signing taking place, you should refuse to notarize the document or otherwise refer to your state notary law for guidance. Here is an article referencing how to notarize for the physically impaired.