The F, M, J, and H-3 visas are designed for students and trainees in the U.S. Each has distinct criteria:
F-1 Visa is for academic students pursuing full-time studies at an accredited U.S. school, including high school, college, or university. Applicants must prove they are enrolled in a full course of study and intend to return to their home country after completion.
M-1 Visa is for students in non-academic or vocational studies. It requires enrollment in a full-time program at a recognized institution, with the intent to return to the home country upon completion.

J-1 Visa is for exchange visitors participating in work-and-study-based exchange programs. It covers a wide range of participants, from students to professors, and often requires the applicant to return home after completing the program.
H-3 Visa is for trainees who wish to receive training in the U.S. in fields such as commerce, communications, or government. The applicant must have a training plan and meet specific program requirements.

All require proof of sufficient funding and intention to depart the U.S. at the end of their stay.