-Do you mean the plastic card? If so, it make takes about one month.
如何获取社会安全号?多谢!
-Did you indicate the SSN request in DS 260 yet? If yes, SSA will send you SSN card a few weeks later after you enter US. If you did not request it in DS 260, then you can go to the local SSA Office to apply for it after you enter US.