ISO/IEC 7810 Identification cards — Physical characteristics is an international standard that defines the physical characteristics for identification cards.

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.