fraud
A fraudulent signature is known as signature forgery. This occurs when someone unlawfully replicates the signature of another person. Signature forgery is either done by copying the signature by freehand or by tracing over the real signature.
If someone forges your signature and uses it for fraudulent purposes, it is considered a crime. Forgery is illegal and punishable by law. The person who forged your signature could face criminal charges and potential legal consequences. It is important to report any instances of signature forgery to the authorities to protect yourself and prevent further fraudulent activity.
the signature of a letter is called the complimentary close or ending
A false signature on a quitclaim deed makes the entire document invalid. No legal property transfer takes place, and the original owner still retains title. A notary public should not have allowed a forged signature on any document, but is not responsible for the crime (I believe) unless he/she knew it was a forgery. (If the document was not notarized, then in most states it could not have been recorded in the courthouse, making it essentially a worthless paper anyway.)
If you mean someone else's signature, it is illegal. It's a forgery. If by signing someone else's signature to a document for gain, it's also fraud.
his signature is called edgecution, a more like DDT...
A person who witnesses a signature is called a witness.
A key signature
Fraudulent
endorcing
The signature on a copy of a document is often referred to as a "signature copy" or simply a "copy signature." It indicates that the signer has authorized or acknowledged the contents of the document, even though it is not the original. In some contexts, it may also be called a "wet signature" if it is physically signed, or simply a "digital signature" if signed electronically.
A signature quote.