Please put your John Hancock on this form.
John Hancock
idiomA person's signature.
Origin
Named after American merchant and statesman John Hancock (1737–1793), the first person to sign the United States Declaration of Independence. According to legend, he signed his name prominently to be sure George III could read it, causing his name to become an eponym for a signature. However, other examples show that Hancock always wrote his signature this way.
The manager asked the client to add their John Hancock to the bottom of the contract.
After reviewing the final terms of the agreement, the CEO finally added her John Hancock to the document, making the partnership official.