Obtaining an M-2 visa is a relatively fast and easy process once your M-1 has been issued. It simply involves verifying the status of the M-1 holder and your relationship to him or her. To bring your dependents on an M-2 visa, they must prove that they are the dependent spouse or child under the age of 21 years and prove their intention to enter the US temporarily.
Adults are permitted to study in a vocational school, and children may study in elementary or secondary schools. Should they decide to study at a full-time academic program, they must apply for a separate M-2 status. Dependents may not be employed while in the United States on an M-2 visa.
Remember, the visa interview process is serious, so prepare ahead of time.