A U.S. visa is an official document that allows a foreign national to enter, stay, or work in the United States for a specific period. There are various types of visas, including tourist visas, student visas, and work visas, each serving different purposes. Applicants must meet certain requirements and go through a process that often includes an interview at a U.S. embassy or consulate. To obtain a U.S. visa, individuals typically need to fill out an application form, pay a fee, and provide supporting documents, such as a passport and proof of financial stability. The visa is usually stamped in the applicant's passport and specifies the duration and conditions of their stay in the U.S.