As an international student or foreign national, you will generally need a visa to enter the USA for any length of time. There are general requirements to gain entry into the USA, in addition to the specific requirements of each visa category.
The F1 Visa is the most popular/ common visa that is issued to incoming students into the USA. Generally it is issued to students who are coming to the USA to study on an academic program or to come to learn English as a Second Language.
An M1 visa is issued to a student who is going to attend a non-academic or vocational school.