To prove your identity and work-authorized immigration status, show your current U.S. immigration documents and your unexpired foreign passport. Acceptable immigration documents include your:
• Form I-551 (includes machine-readable immigrant visa);
• Form I-94 (Arrival/Departure Record) showing DHS work authorization; or
• Forms I-766 (Employment Authorization card).
If you are a J-1 or J-2 exchange visitor, you will also need to show your DS-2019, Certificate of Eligibility for Exchange Visitor Status. If you are a J-1 student, student intern, or international visitor, you must provide a letter from your sponsor. The letter should be on sponsor letterhead with an original signature that authorizes your employment.
If you are an F-1 or M-1 student, you need your Form I-20, Certificate of Eligibility for Non immigrant Student Status. For information on other documents students must provide, ask for International Students And Social Security Numbers (Publication No. 05-10181).
You must present your foreign birth certificate if you have it or can get it within 10 business days. If not, other documents, such as your passport or a document issued by DHS, will be considered as evidence of your age.
To answer any other question you may have about social security numbers, you may go here: http://www.ssa.gov/pubs/10096.html.