In general, the B Visa allows individuals to visit the US temporarily for business (B-1 Business Visitor) or for pleasure (B-2 Tourist Visa). Nationals of certain countries can also visit the US temporarily without a visa if they qualify for the Visa Waiver Program (VWP).
The B-1 Business Visa enables business visitors to the US to engage in business activities such as meetings or conferences. However, the B-1 Business Visa category is not to be used for anything that could be construed as meaningful work or employment in the United States.
In the context of the B-1 Business Visa, “Business Activities” refers to conventions, conferences, consultations and other legitimate activities of a commercial or professional nature, not including local employment or labor for hire.
Honoraria Payments: B-1 Business Visa holders who engage in activities at certain higher educational institutions, related nonprofit organizations, or nonprofit or governmental research organizations are authorized to receive honoraria payments and incidental expenses for usual academic activities lasting no more than 9 days at any single such institution or organization. More information on B-1 Visa Honoraria.
The B-2 Tourist Visa enables foreign nationals to travel temporarily in the US. Such trips cannot involve employment, and the length of stay may be up to one year. Note that nationals of countries participating in the Visa Waiver Program (VWP) may enter the US without a visa and stay for a period of up to 90 days. However, if one enters under the Visa Waiver Program rather than obtaining an actual B visa in the passport at a US consulate, a change of status to other nonimmigrant or immigrant visa categories is not permitted while inside the US, nor is an extension of temporary status or adjustment to permanent residence.