A visa does not guarantee entry into the United States, but allows a foreign citizen coming from abroad, to travel to the United States port-of entry and request permission to enter the United States. The Department of Homeland Security, United States Customs and Border Protection (CBP) officials have the authority to permit or deny admission to the United States, and determine how long a traveler may stay. At the port of entry, you will be provided with a small white card, Form I-94, Arrival-Departure Record. It is usually attached to your passport. Customs and Border Protection Officers record either a date or “D/S” (duration of status). If your I-94 contains a specific date, then that is the date by which you must leave the United States. Your Form I-94 is a very important document, since it shows you are allowed to be in the United States up to a specific date or for the duration of your status.