Once you have been admitted by an American university, your university will send you an I-20 to enable you to enter the U.S. on an F-1 (student) visa. The I-20 is a certificate of non-immigrant eligibility i.e. it certifies that you are eligible to travel to the United States as a student and are not traveling as an immigrant. This document, sometimes referred to as a DS-2019, is usually sent to you by the admissions office in your university.
The I-20 certifies that you have enough financial resources to attend school and pay for your living expenses while attending school without resorting to illegal employment or relying on public funds. For this reason, the I-20 states: