A more thorough explanation:

A nonimmigrant visa is a type of visa that allows foreign nationals to temporarily stay in the United States for various purposes such as study, work, tourism, business, medical care, and more. The visa is placed in the traveler's passport once issued. The type of nonimmigrant visa required is determined by the applicant's purpose of travel.

There are over 30 categories of nonimmigrant visas, each with a letter designation. Some examples include:

• B-1: Temporary visitors for business
• B-2: Temporary visitors for pleasure/tourism
• F-1: Students
• H-1B: Workers in specialty occupations
• J-1: Exchange visitors
• O-1A: Individuals with extraordinary ability or achievement in sciences, arts, education, business, or athletics
• P-1A: Athletes who attend an internationally recognized level of sustained performance
• Q: International cultural exchange program participants
• U-1: Victims of criminal activities
• T-1: Victims of human trafficking

The purpose of entry and the applicant's qualifications determine the type of nonimmigrant visa required. For example, a foreign student attending an academic institution in the United States would need an F-1 visa, while a worker in a specialty occupation would need an H-1B visa.

Overall, nonimmigrant visas allow foreign nationals to temporarily stay in the United States for various purposes, but they must leave the country once their visa expires or their purpose of travel is complete.