I am not really sure how many visas there are to come to the United States although it seems that most people come here on a tourist visa. There are other types as well such as:

-Student or Exchange Student Visa
-Work Visa
-Immigrant Visa

Under these visas there are various types as well. Each visa requires different kinds of evidence or proof for the reason that you are visiting/immigrating to the United States and also some kind of financial support while you are in the country.

Have you ever traveled to the United States? If so, what type of visa did you get? Explain any experiences you might have encountered.