What is the difference between an immigrant visa and a non-immigrant visa?
There are two basic categories of visa, an immigrant visa and a non-immigrant visa.
Non-immigrants are aliens who are coming to the United States for a temporary period of time and for a specific purpose. For example, if you are coming to the United States as a temporary visitor for pleasure, under U.S. law you would apply for a B-2 visa. If granted, you may come to the U.S. for a temporary period of time and you may only engage in activities consistent with being a visitor, such as sightseeing, visiting friends and relatives. You would not be permitted to enroll in school and study nor would you be allowed to work, as that is not consistent with a B-2 visa. If you are in the United States on a tourist visa, it is possible to change status to a different category, such as student, assuming you qualify.
Immigrant visas are for aliens who are entering the U.S. with the intention of becoming a permanent resident. Immigrant visas are subject to numerical limitations. This means that each of the immigrant visa categories has a certain number of allotted slots for visas. Once the quota is filled, a waiting list is created that will delay your arrival into the United States.