Different student visas to the US

The immigration law allows foreign nationals to study in the United States. These foreign nationals must attend a school in the United States that has been approved by the USCIS for such attendance. These schools must be approved by USCIS to enroll foreign nationals. The foreign national (student) from abroad who wishes to enter United States for the purpose of education must obtain a student visa which will be placed in the passport of the individual. The student visas are classified into two types.

F student visa (Academic Course)
M student visa (Non-academic or vocational course)

The F visa is classified into F1 and F2 visas. F1 visas are used by non-immigrant students for Academic and Language training Courses. The F2 visas are used by the dependents of F1 visa holders. Spouse and unmarried, minor children are said to be the dependents of the F1 visa holder. The M visa is classified into M1 and M2 visas. M1 visa is used by a person who wishes to do non-academic or vocational course. The M2 visas are given to the dependents (spouse and unmarried, minor children) of the M1 visa holder. The F2 and M2 dependents must meet all the eligibility requirements and must provide evidence that they will be able to support themselves financially and will leave United States once the student's course concludes.

General eligibility requirements for a US student visa

The Immigration and National Act is specific about the requirements that must be met by the applicants in order to qualify for the student visa. It is the decision of the consular officer whether the applicants will be approved the student visas or not. Additionally, all the applicants are required to meet the eligibility requirements such as,

the applicant must have a residence abroad with no intention of abandoning the residence.
must intend to leave United States when the course concludes
also must possess valid funds to complete the proposed course of study

In addition to the basic eligibility requirements the applicant must provide the following to obtain the student visas:

submit Form I-20A-B (Certificate of Eligibility for Non-immigrant (F-1) Student Status-For Academic and Language Students) or Form I-20M-N (Certificate of Eligibility for Non-immigrant (M-1) Student Status for Vocational Students).
submit a SEVIS generated Form, I-20, which was at the applicant's school. The applicant and the school official must sign the I-20 form.
must have a valid passport to travel to the United States.
must provide transcripts and diplomas from previous institutions attended, and
a financial statement to prove that the applicant will be supported financially for the stay in United States, course and living expenses during the period of stay.

On entering the United States on a student visas, the students will be allowed to stay the duration of the student status. Even if the F1 visa in the passport expires the student may stay in US if the applicant is a full time student. But however the applicant must obtain a new visa applying at the embassy abroad before returning to the United States to resume the studies.