A travel document is an identity document issued by a government or international entity pursuant to international agreements to enable individuals to clear border control measures. Travel documents usually assure other governments that the bearer may return to the issuing country, and are often issued in booklet form to allow other governments to place visas as well as entry and exit stamps into them.

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.