A passport is an official government document that certifies a person's identity and nationality. It allows individuals to travel internationally and serves as proof of citizenship. Passports typically include personal information such as the holder's name, date of birth, and photograph, along with an expiration date. When traveling to another country, a passport is often required for entry. It may also be necessary to obtain a visa, which is a separate document granting permission to enter a specific country. Many countries have specific regulations regarding passport validity, so travelers should ensure their passport is up to date before planning a trip.