The following visa classifications have study restrictions. If you are in the U.S. in B-2 or F-2 status, you will not be able to begin a full course of study until your status is changed.

If you are a student seeking admission or recently received admission to the university and you have a B-2 entry visa in your passport, you should not use the B-2 or WT status to enter the U.S.

B-1 and B-2
B-1 visitors for business and B-2 visitors for pleasure are prohibited from "enrolling in a course of study" unless they apply for and USCIS approves a change from B status to F-1 or M-1 student status.
A B visitor who begins a course of study prior to the approval of a change of status application is considered to have violated a condition of his or her immigration status. USCIS will deny a change of status request if the B-1 or B-2 nonimmigrant enrolled in a course of study before filing the application for change of status or while the application is pending before USCIS

The F-2 spouse of an F-1 student may not engage in full time study, and the F-2 child may only engage in full time study if the study is in an elementary or secondary school (kindergarten through twelfth grade). The F-2 spouse and child may engage in study that is avocational or recreational in nature.
Part-time study that is avocational or recreational in nature

F-2 dependents may "engage in study that is avocational or recreational in nature." For example: If a student engages in study to pursue a hobby or if the study is that of an occasional, casual, or recreational nature, such study may be considered as avocational or recreational and may be engaged in on a part-time basis.