An I-20 Student Visa is essential to studying in the US. It serves as proof that an international student has been admitted into an approved program and has sufficient financial resources for tuition and living costs without using illegal employment or public funds as a fallback option. Furthermore, this document must also be presented when applying for either F1 or M 1 student visa categories.
Once accepted to a US university, your personal details are entered into the SEVIS database by your Designated School Official (DSO). Your i-20 form contains all relevant official information regarding your course of study in the US such as start/end dates, estimated costs and funding sources; to verify its legitimacy you should check with ISSS.
Arriving in the US at least 30 days prior to your course start date on your I-20 is recommended in order for your DSO to validate your arrival in SEVIS and record your intent to study. Failing to do this could result in you falling out of status, potentially making reentry impossible in future.
The I-901 fee can be paid online through the Department of Homeland Security website using debit/credit card, cheque or international money order. A third party (for example a sponsor) may also make this payment on your behalf and it would be prudent to save their receipt in case this form of proof of payment is required when applying for your visa.