The F-1 Visa is the most common type of student visa availed by students all over the world to come to the USA. The F-1 Visa is granted to students who want to come and study in an academic studies and/or language programs. For non academic programs an M visa is issued.
F-1 visa holders may work in the USA with approval from the United States Citizenship & Immigration Service (USCIS). They can work inside the University for 20/hours/week. Curricular Practical Training (CPT) work authorization allows you to work outside in a job that is related to your field of study.
Hower, F-1 visa holders have to maintain good grades over the period of employment. During this period they have to report to their International Student Advisor regularly. In a recent development from USCIS students enrolled in courses in Science, Technology, Engineering and mathematics may apply for a work authorization under Optional Practical training for another 29 months after they graduate.
M visa or the Vocational Visa as it is called is another kind of a visa which is granted to students who want to come to the USA for Education courses which are non-academic in nature. Generally the students who come to the USA on M visa study in technical or vocational schools. Students on M visa are not eligible for a visa more than 1 year at a time, under normal circumstances, unless there is a medical emergency.
They are also given Optional Practical Training work authorization - but for a very short amount of time. It is granted for 1 month for every 4 months of the program. M visa holders have an expiry date on their I-94 unlike their F-1 Counterparts who don't have an expiry on their I-94. M visa holders are not allowed to work on or off the campus while studying and they are not permitted to change their status to F-1 inside the USA.
This Visa is issued to students who want to come to USA on exchange programs. The purpose of this Visa is to promote cultural exchanges.
Students must meet certain admission criteria and they should be sponsored by a private sector or government program. Exchange visitors are expected to leave the USA upon the completion of their program.
The dependents of J-1 visa are granted J-2 visas and are not allowed to work in the USA unless authorized. But they can study in the USA without having to apply for an F-1 Visa.