The Embassy may give you a sealed envelope to take with you to the US, which must be surrendered to the Immigration official at the gate at the airport on arrival.

Also, check your passport, it should be stamped with “Authorized to Work”. If this is the case you should be able to use this for employment for up to 90-days. If you remember, check with the Embassy official regarding the ‘authorization to work’ stamp to confirm that you can actually work on it. The reason why counsel is not 100% clear on this point is that counsel has found that some states treat this authorization differently.

K1 Fiance Visa Guide