The purpose of a passport is to serve as an official government document that identifies a person and verifies their nationality or citizenship while traveling internationally. It is essential for accessing entry into foreign countries, as it contains personal information, including the individual's name, photo, date of birth, and identification number. Additionally, a passport allows travelers to obtain visas when required by the destination country. It also helps to ensure security and border control by proving the traveler’s identity, thus facilitating international travel in a regulated manner and protecting national sovereignty.