this is from their website. What is I-551?

来源: 于 2007-10-25 11:59:00 [旧帖] [给我悄悄话] 本文已被阅读：次

If you are not a U.S. citizen, Social Security must see your current U.S. immigration documents. Acceptable documents from the Department of Homeland Security include your:

Form I-551 (includes machine-readable immigrant visa with your unexpired foreign passport);
I-94 with your unexpired foreign passport; or
Work permit card (I-766 or I-688B).