Applying for a visa to enter the United States, either as a temporary visitor or with the intent of becoming a permanent resident, can be confusing. The following answers to some of the most frequently asked visa questions should help with this process:
Usually, but a visa is no guarantee that you will be admitted into the country. Visas do in fact grant a foreign citizen's entry to a U.S. port-of-entry, such as an airport, but admission past the port-of-entry is determined by a U.S. Dept. of Homeland Security (DHS) immigration inspector.
For questions about U.S. visas and inquiries related to visa denial, you should contact the Dept. of State or the embassy or consulate abroad. But once you are in the U.S., your visa status falls under the jurisdiction of U.S. Citizenship and Immigration Services (USCIS), a division of the DHS. For travelers already in the U.S., the DHS handles petitions, work authorization, extensions and adjustment of status.
Your visa is valid for a specified amount of time, so it becomes invalid after the expiration date. But it does not necessarily mean you may stay in the country until that date, only that you may make repeated visits while the visa is still valid. The length of stay is approved at the port-of-entry by a DHS inspector.
A DHS immigration inspector will give you a small white card called an Arrival-Departure Record (Form I-94, I-94W if you are participating in the Visa Waiver Program) upon arrival at a U.S. port-of-entry. The inspector records a duration of status or a specific date. If a specific date is given, then you must leave the U.S. before that date.
Consider speaking with an immigration attorney if you have additional visa questions.
Contact a qualified immigration attorney to help you with visa procedures.