A visa is issued by a U.S. Embassy or Consulate. A visa entitles the holder to travel to the United States and apply for admission; it does not guarantee entry. An immigration inspector at the port of entry determines the visa holder's eligibility for admission into the United States.
Who needs a visa? Anyone who is not eligible to enter the United States visa free under the Visa Waiver Program (VWP), or is not exempt from the visa requirement. Please note: Travelers born in the United States and those who hold dual citizenship with the United States must enter and depart the United States on U.S. passports.