An identity document is any document that may be used to prove a person's identity. If issued in a small, standard credit card size form, it is usually called an identity card, or passport card. Some countries issue formal identity documents, as national identification cards that may be compulsory or non-compulsory, while others may require identity verification using regional identification or informal documents. When the identity document incorporates a person's photograph, it may be called photo ID.

A driver's license, driving licence, or driving permit is a legal authorization, or the official document confirming such an authorization, for a specific individual to operate one or more types of motorized vehicles—such as motorcycles, cars, trucks, or buses—on a public road. Such licenses are often plastic and the size of a credit card.