There are TWO types of subscribing witnesses.
1. The person who appears before a Notary on behalf of someone being notarized with a Proof of Execution is called a subscribing witness or executing witness. The actual signer cannot appear before a Notary Public, so a witness is used to sign on the principal’s behalf and swear. The basic idea is that the subscribing witness witnessed the principal sign the document.
2. A person who witnesses a disabled person who is signing by X in a document is also called a subscribing witness.
As a Notary Public, you may come into a situation where the signer is not able to sign. Most Notaries are not trained in how to handle such situations. If you do hospital notarizations you will deal with this situation a lot. Some signers cannot move their arms properly. Others cannot sign their name. If you can get them to sign an X in your journal and an X in the signature section of the document with two subscribing witnesses watching. You are in luck.
You need to have the subscribing witnesses sign your journal and input their drivers license info as well. Additionally, the subscribing witnesses sign the first and last name of the signer on the document which sounds like forgery, but many states allow this. Check your state notary handbook to see if this procedure is legal in your state.
Signature by X from A to Z
Subscribing Witness Glossary Definition
What is Signature by X or Signature by Mark
Types of witnesses in the notary profession