Immigrant visas based on employment are a path to obtaining permanent residency ("green card") and are based on the applicant's professional qualifications. In most cases, spouses and children under 21 can accompany immigrants based on these categories.
Immigrant family visas are designated for some relatives of U.S. citizens and permanent residents who want to sponsor their loved ones to live and work legally in the U.S., obtaining green cards and citizenship.
A Non-Immigrant visa is designated for people who will temporarily visit the U.S. Temporary visits include a wide variety of purposes such as tourism, study, or work, with various durations of stay.