The US government issues more than 30 different types of visa. For example, tourists and business-men are issued B-1 or B-2 visas and those authorized to work in US are given an H-1B visa. Students going for vocational courses, such as, in flying schools or English language courses get an M-1 visa. However, most students require an F-1 visa stamp.
This is the most commonly issued type of visa for students going to an accredited university for a full-time academic program lasting for one or more years.