J1 exchange visa is for persons who want to travel to the US for the following:
J1 exchange visa is only for specific educational and cultural exchange programs designated by the US Department of State. The US Department of State website provides detailed information on J1 exchange visas.
J1 exchange visa applicants must have a US Department of State designated sponsor. The sponsor will send the “DS-2019 Form” after the applicant is accepted. The DS-2019 Form is a confirmation form for applicants which sets out various details about the specific type of program. Applicants can only apply for a visa after receiving the DS-2019 Form from their sponsor.
US State Department - J1 Exchange Visa
Foreign Affairs Manual - J1 Exchange Visa