Each category has specific requirements as briefly described below:
First preference EB-1:
This preference is reserved for persons of extraordinary ability in the sciences, arts, education, business, or athletics; outstanding professors or researchers; and multinational executives and managers.
Second preference EB-2:
This preference is reserved for persons who are members of the professions holding advanced degrees or for persons with exceptional ability in the arts, sciences, or business. Generally, a Labor Certification from the U.S. Department of Labor is required, unless the applicant is able to apply for the National Interest Waiver.
Third preference EB-3:
This preference is reserved for professionals, skilled workers, and other workers.
Fourth preference EB-4:
This preference is reserved for “special immigrants,” which includes certain religious workers, employees of U.S. Foreign Service posts, retired employees of international organizations, alien minors who are wards of courts in the United States, and other classes of aliens.
Fifth preference EB-5:
This preference, also known as the Immigrant Investor Program, is designed to stimulate the U.S. economy through job creation and capital investment by foreign investors. All EB-5 investors must invest in an enterprise that will create or preserve at least ten full-time jobs for qualifying U.S. workers within two years of the immigrant investor’s admission to the United States as a Conditional Permanent Resident.
Generally, the required minimum investment is $1 million. However, if the investment is made in a targeted employment area – high unemployment or rural area – the minimum qualifying investment is $500,000.
You can find a list of current EB-5 (immigrant investor) regional centers by state here