A visa is a sort of permission given by the country to enter their premises.
No, a Visa is not the same as a passport. A visa is permission given by the host country to enter their premises.
There are more than 180 types of US visas which are then grouped into two main categories immigrant and non-immigrant visas
What are the Main Types of Visas in the USA
· Visitor visas (B1 and B2) · Student visas (F1, F2, M1) · Exchange visitor’s visa (J1, Q) · Temporary Work Visas (H1B, H1B1, H-2A, H-2B, H-3, L1, O1, O2, O3, P, TN/TD, E3, I) · Treaty trader and investor visas (E1, E2) · Diplomatic and Official Visas (A1, A2 NATO1-6, G-1, G-5) · Visas for victims of crime and human trafficking (T, U)