There are more than 20 nonimmigrant visa types for people traveling to the United States temporarily. There are many more types of immigrant visas for those coming to live permanently in the United States. The type of Visa you need is determined by the purpose of your intended travel.

No. If the Department of Homeland Security, Customs and Border Protection Immigration Officer at the port-of-entry admitted you into the United States for a specific period of time, s/he will note your authorized period of stay on your admission stamp or paper Form I-94, called an Arrival/Departure Record. You will be able to remain in the United States during your authorized period of stay, even if your visa expires during the time you are in the United States. Since your admission stamp or paper Form I-94 documents your authorized stay and is the official record of your permission to be in the United States, it is very important to keep inside your passport.

The fee that you paid is an application fee. Everyone who applies for a U.S. visa anywhere in the world must pay this fee, which covers the cost of processing your application. This fee is non-refundable regardless of whether you are issued a visa or not, since your application was processed to conclusion. As one example, if your application was refused under Section 214(b) and you choose to reapply for a visa, whether applying at the same embassy or elsewhere, you will be required to pay the visa application processing fee.