Some of the limitations of an M-1 visa are:
You cannot enter as an M-1 to study “generally.” Your program must have a goal, and you must be involved in a full course of study;
You are not permitted to work during the course of your studies;
You may transfer from one school to another only with the permission of the Department of Homeland Security and U.S. Citizenship and Immigration Services (USCIS) within certain time parameters;
Your dependents may enter the country but are not permitted to work, and;
Once you are six months into the program of study, you are prohibited from changing your course of study except under truly exceptional circumstances.