Per federal regulations, B-1 and B-2 nonimmigrants (i.e., visitors who are in the United States for business and pleasure purposes) are prohibited from enrolling in a course of study at a U.S. Student and Exchange Visitor Program (SEVP)-certified school.
If you are a B-1 or B-2 nonimmigrant and wish to study at a U.S. school, you must file a Form I-539, “Application to Extend/Change Nonimmigrant Status,” with the U.S. Citizenship and Immigration Services (USCIS) to change to either an F-1 or M-1 status and pay the required fee and include the required documents listed in the instructions.
While your Form I-539 is pending, you must maintain your B-1 or B-2 status and cannot enroll in your SEVP-certified program until USCIS approves your change of status request. Enrolling in a course of study as a B-1 or B-2 nonimmigrant, prior to receiving authorization, will result in a status violation and ineligibility to extend your B status or change to F-1 or M-1 status in the future.
If USCIS has not adjudicated your change of status at least 15 days before the program start date on your Form I-20, “Certificate of Eligibility for Nonimmigrant Student Status,” contact the designated school official at your new school as you may need to defer your attendance to a later start date.
USCIS may only approve your Form I-539 change of status request if you are maintaining your B-1/B-2 status up to 30 days before your program’s initial start date. This means that under certain circumstances, you may need to file a second Form I-539, with a separate fee, to request an extension of your B-1 or B-2 status. Because extending your current stay in B-1 or B-2 status and changing from B-1 or B-2 to F-1 or M-1 status are two distinct benefits, you must pay a separate filing fee for each request.
LINK: https://studyinthestates.dhs.gov/2017/05/b-1b-2-visitors-who-want-to-enroll-in-school