To study as an F-1 student in the United States, you need a Form I-20. The F-1 student visa allows you to enter the United States as a full-time student at an accredited institution. The Form I-20 is also known as a “Certificate of Eligibility for Nonimmigrant Student Status”. This document provides supporting information on a student’s F-1 status. All F-1 students, who study in the United States, need a Form I-20.