If you are planning to enter the US to study at one of the US-based schools, you will have to submit a J1 Visa. The J1 visa applies to exchange visitors. For those who have already been able to the US before for studies, you will have to get a J1 Visa Renewal first.
As part of your J1 Visa Renewal, you will have to secure the Certificate of Eligibility for Exchange Visitor first, also known as Form DS-2019. If you are an exchange visitor who left US territory on or after the 15th of February in year 2003, you have to secure SEVIS-generated documents. This also means you are subject to SEVIS rules.
If you already have your Form DS-2019, you have to submit this SEVIS-generated document to the US embassy for electronic verification. For those who departed the US before February 15, 2003, your data as encoded in the ISEAS (Interim Student and Exchange Authentication System) will still be used by the consulates where applicable.
Check your Form DS-2019 regarding the start date because you will not be allowed to enter the US until at least thirty days before the indicated start date. This is very important for J1 Visa Renewal. It is equally important to still present your original Form DS-2019 (SEVIS-generated) as well as proof that you still have ties to the country where you originated from. You should also show that you have paid for your SEVIS fee. You must also provide evidence that you have the means to pay for your studies in the US.