Social Security Number
The 9-digit U.S. Social Security Number (SSN) is the official identifying number used for U.S. tax reporting purposes. SSNs generally are assigned to people who are authorized to work in the United States. SSNs are used to report your wages to the government and to determine eligibility for Social Security benefits, generally when you reach retirement age.
International students are not eligible for SSNs unless they have a job offer and will be working in the U.S. Instructions for each eligibility status are available.