There are a number of different types of US visas, and you may need to apply for more than one type.
The two main types of US visas are tourist and non-immigrant visa.
A tourist visa allows you to visit the United States for a certain amount of time and to return home when your time is up. The visa is valid for up to six months. If you want to stay in the country longer, you must apply for a different type of visa—such as an H1B Visa or F1 Visa—which allows you to work in the United States.
A non-immigrant visa allows you to stay in the country permanently under specific conditions. You must meet these conditions before applying for this type of visa. For example, if you want to work in the United States on this kind of visa, then you must first obtain an offer from an employer who will sponsor your work application.