A visas are issued to representatives of a foreign government traveling to the United States to engage in official activities for that government. A visas are granted to foreign government ambassadors, ministers, diplomats, as well as other foreign government officials or employees traveling on official business (A-1 Visa). Certain foreign officials require an A visa regardless of the purpose of their trip. The A visa is also granted to immediate family members of such foreign government officials, defined as “the principal applicant’s spouse and unmarried sons and daughters of any age who are not members of some other household and who will reside regularly in the household of the principal alien” (A-2 Visa) and which “may also include close relatives of the principal alien or spouse who are related by blood, marriage, or adoption who are not members of some other household; who will reside regularly in the household of the principal alien; and who are recognized as dependents by the sending government (A-3 Visa).
B-1 and B-2
The most common non-immigrant visa is the multiple-purpose B-1/B-2 visa, also known as the “visa for temporary visitors for business or pleasure.” Visa applicants sometimes receive either a B-1 (temporary visitor for business) or a B-2 (temporary visitor for pleasure) visa, if their reason for travel is specific enough that the consular officer does not feel they qualify for combined B-1/B-2 status. Holders may also attend short non-credit courses. Mexican citizens are eligible for Border Crossing Cards.
From November 29, 2016, all holders of Chinese passports who also hold 10-year B visas are required to enroll in the Electronic Visa Update System (EVUS) before travelling to the United States. This requirement may be extended to other nationalities in the future.
C-1 visa is a transit visa issued to individuals who are travelling in “immediate and continuous transit through the United States enroute to another country”. The only reason to enter the United States must be for transit purposes. A subtype C-2 visa is issued to diplomats transiting to and from the Headquarters of the United Nations and is limited to the vicinity of New York City. A subtype C-3 visa is issued to diplomats and their dependents transiting to and from their posted country.