United States passports are issued to anyone who can prove their American nationality. Holding an American passport entitles the bearer to freedom of movement and the right to work and live in the USA. United States passports are the most common travel document issued to American nationals. Holding a US passport is a big convenience as it exempts US nationals from applying for visas to travel to many other countries because the US has many reciprocal visa waiver agreements around the world. The US passports are issued exclusively by the US Department of State in two formats: passport book and passport card.
USA passport books are valid for traveling to any country in the world. Some countries require US nationals to obtain a visa additionally to having a valid US passport before they enter this country. To facilitate travel, American passports conform with the recommended standards of the International Civil Aviation Organization. There are five types of passport books: US regular passport, US official passport, US diplomatic passport, US refugee passport and US emergency passport. As of 2007, the Department of State is issuing only biometric, or e-passports, although non-biometric passports are still valid until their expiration dates.
The US Department of State started issuing US passport cards since 2008. They are valid for travels by American nationals to Mexico, the Caribbean, Bermuda and Canada if they travel by land or sea. Passport cards cannot be used for air travel or for travel to another country except from those listed above.
The US passports confirm the nationality of its holder, and therefore the rights of assistance from US Embassy or consulate offices abroad. If a US citizen has lost their US passport, or it was stolen, they can approach the US embassy abroad for a right to return to the US, provided they can prove their US nationality.