There are two nonimmigrant visa categories for persons wishing to study in the United States (a nonimmigrant is someone admitted to the U.S. temporarily):
"F" visa includes academic students in colleges, universities, seminaries, conservatories, academic high schools, other academic institutions, and in language training.
"M" visa is for people wishing to pursue nonacademic or vocational studies.
Am I Eligible?
To be eligible to apply for the F or M visas, you must intend to stay for a temporary period of time and have proof of compelling ties (social, family, economic, professional or other) to a residence outside the United States to which you will return after the visit. You must also meet the following criteria:
You must have successfully completed a course of study normally required for enrollment. Unless you are coming to participate exclusively in an English language training program, you must either be sufficiently proficient in English to pursue the intended course of study, or the school must have made special arrangements for English language courses or teach the course in your native language.
You must prove that sufficient funds are, or will be, available from an identified and reliable financial source to defray all living and school expenses during the period of your study in the U.S. Specifically, you must prove that you have enough readily available funds to meet all expenses for the first year of study, and that adequate funds will be available for each subsequent year of study. If you are applying for an M-1 visa, you must have evidence that sufficient funds are immediately available to pay all tuition and living costs for the entire period of your intended stay.
You must be accepted as a full-time student in a U.S. academic educational program, language-training program, or vocational program. The school must be approved by the Immigration and Naturalization Service (INS), and the school must send you a Form I-20 (which it receives from the INS).