An endorsement can refer to several different things, including:

• Signature endorsement: This is a signature or equivalent stamp that authorizes payment or a transfer of funds, or other financial transaction.

• Amendment to a contract or document: An endorsement can also refer to a note, amendment, or clause to an official document or contract that modifies or specifies terms.

• Public declaration of support: A public declaration of support for a person, product, or service is also called an endorsement. This can occur when a government official, an influential person, or an organization expresses their support for a political candidate or a product.

• Insurance endorsement: An insurance endorsement, also known as a rider, is an amendment to an existing insurance contract that changes the terms of the original policy.

• Commercial endorsement: This occurs when someone, often a celebrity or public figure, is paid to promote a product or service.

Endorsements can be a form of advertising that uses famous personalities or celebrities who command a high degree of recognition, trust, and influence. They can also be used to alter the terms of an insurance policy or to show support for a political candidate or product.