A U.S. passport is an official document issued by the United States government that certifies a person's identity and citizenship. It allows American citizens to travel internationally and serves as proof of identity when entering foreign countries. The passport contains personal information, including the holder's name, date of birth, and photograph. To obtain a U.S. passport, individuals must apply through the U.S. State Department and provide necessary documentation, such as proof of citizenship and identification. Passports are typically valid for ten years for adults and five years for minors, and they must be renewed upon expiration.