A non immigrant visa is used by tourists, business people, students etc. who wish to stay for a particular period of time in the United States to accomplish specific purposes.
Visas are available under different categories:
Business/Tourist Visa: The B-1/B-2 visitor visa is for people traveling to the United States temporarily for business (B-1) or for pleasure or medical treatment (B-2). Often, the B-1 and B-2 visas are combined and issued as one visa: the B-1/B-2.