An identity document (also called a piece of identification or ID, or colloquially as one's 'papers') is any document which may be used to verify aspects of a person's personal identity. If issued in the form of a small, mostly standard-sized card, it is usually called an identity card (IC or ID card). Countries which do not have formal identity documents may require identity verification using informal documents.
In the absence of a formal identity document, driving licences may be accepted in many countries for identity verification. Some countries do not accept driving licences 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 residence permit in the country.
The personal information present on the identity document, or in a supporting database, might include the bearer's full name, a portrait photo, age, birth date, address, an identification number, profession or rank, religion, ethnic or racial classification, restrictions, and citizenship status.