Identity document

An identity document (also called a piece of identification or ID, or colloquially as papers) is any document which may be used to identify a person or verify aspects of a person's personal identity. If issued in a small, standard credit card size form, it is usually called an identity card (IC or ID card). Some countries issue formal identity documents, while others may require identity verification using informal documents. When the identity document incorporates a person's photograph, it may be called photo ID.

In the absence of a formal identity document, a driver's license may be accepted in many countries for identity verification. Some countries do not accept driver's licenses for identification, often because in those countries they do not expire as documents and can be old or easily forged. Most countries accept passports as a form of identification.

Some countries require foreigners to have a passport or occasionally a national identity card from their country available at any time if they do not have a residence permit in the country.