If you are granted a study permit, you are automatically also granted permission to work part-time for up to 20 hours per week, including remote work, in addition to your studies and full-time during holidays.
You can apply for a permit to work full-time during the academic year if the work is part of your education plan. You have to ask for this in writing when you apply, or later.
You can not be self-employed or run your own business in Norway