BEFORE: You apply for a Visa, You must have a Passport!
A passport is an internationally recognized travel document that verifies the identity and nationality of the holder. U. S. citizens are required to have a valid U.S. passport to enter and leave most foreign countries. The U.S. Department of State is the only authority that can grant, issue, or verify U.S. passports.
Note for Your Parents: Because applying for a passport is a lengthy process, suggest to your parents that they should also have/get a valid, up-to-date passport. In the unlikely event of your having a life-threatening illness or an emergency, they would be able to travel more quickly to your host country.
APPLYING: For a Visa!
A visa is an official stamp or document affixed within a passport, or given to you as a separate document, that has been issued by a foreign government granting permission for entry specifically to study, work, or live in a particular country. There is no right to a visa, even upon presentation of all required documents.