A visa to the U.S. is a document that gives a non-U.S. citizen or non-permanent resident an opportunity to apply for admission into the United States for a designated purpose.
Generally speaking, to obtain entry into the United States, an alien must apply for a visa at a U.S. consulate or embassy abroad. U.S. consular officers will review an alien's visa application and decide whether to issue a visa to the alien. U.S. consular officers have a wide range of discretion with regards to approving or denying a visa application, a denial could be for any reason or no reason at all.
If the Consular Officer grants a visa to the alien, then the applicant will have an allotted time frame, depending on the type of visa issued, to go to a U.S. port of entry and apply for admission into the U.S. A U.S. port of entry is located either at the border of the United States or at a U.S. international airport. At the port of entry, the alien applies for admission into the U.S. with an officer of United States Customs and Border Protection (CBP). Although an alien may possess a valid visa, the border officer can deny the alien’s application for admission to the U.S. For information regarding the entry process and reasons for denial of entry when an alien has a valid visa, please click here.
For more information on non-immigrant visas, please click on the following links: