A visa is a photo i.d. granted outside of U.S. borders that enables you to enter the U.S. on a temporary or permanent basis. There are two main kinds of visas: •    immigrant (permanent residency) visas, also named green cards, that enable you to live and work for an indefinite period of time in the U.S.; and •    non-immigrant visas, which enable you to live and/or work in the U.S. for a definite period of time.  If you apply from inside the U.S., you might be granted a non-immigrant status, not a visa. Only a visa allows you to enter the U.S. For example, if you wanted to travel outside the U.S. with a valid status, you would have to reapply for a visa in order to enter the country again.