A student visa provided by the host country confirms that your child is approved to study there. Your child student visa allows them stay in your host country longer than a typical tourist. Visa requirements and application processes differ by country, so you and your child should contact the host country embassy or consulate to learn the specifics for your trip.
Each applicant for a student visa must submit these forms and documentation as explained below:

Form I-20A-B, Certificate of Eligibility for Nonimmigrant (F-1) Student Status-For Academic and Language Students or Form I-20M-N, Certificate of Eligibility for Nonimmigrant (M-1) Student Status for Vocational Students. You will need to submit a SEVIS generated Form, I-20, which was provided to you by your school.You and your school official must sign the I-20 form. See the previous section for SEVIS information.
Online Nonimmigrant Visa Electronic Application, Form DS-160. Visit our DS-160 webpage to learn more about the DS-160 online process.
A passport valid for travel to the United States and with a validity date at least six months beyond the applicant intended period of stay in the United States (unless country-specific agreements provide exemptions). If more than one person is included in the passport, each person desiring a visa must complete an application.
One (1) 2x2 photograph. See the required photo format explained in Photograph Requirements;
A MRV fee receipt to show payment of the visa application fee.
The SEVIS I-901 fee receipt.

I think you should visit this link where you can get all the information you needed regarding Visa for studying abroad-

http://www.diversityabroad.com/parents/student-visa