In the United States, the F visas are a type of non-immigrant student visa that allows foreigners to pursue education in the United States. F-1 students must maintain a full course of study. F-1 visas are only issued in U.S. embassies and consulates, although extensions of stay and changes of status may be possible within the United States. Prospective F-1 students must apply to a school and receive a form I-20 in order to apply for an F-1 visa. F-1 students must show that they are able to support themselves during their stay in the U.S., as their opportunities for legal employment are quite limited. F-2 visas are given to dependents of an F-1 student. F-2 visa-holders are prohibited from any form of compensated employment. However, minor children may attend public schools. Finally, the F-3 visa is issued to Canadians and Mexicans who commute across the border to attend American schools.