回複：FP --What is the diffrence between code 3 and code 2?

Code 1 is all 10 FP. This is electronically sent to FBI the same day, they run it to match thru their database to match it with criminals/persons of interest and send the results the same day (or the next) to USCIS. Code 1 is very important as it is part of your security/background check and determines admissibility for gc.

Code 2 (index+photo+sign) is for the generation of cards for immigration benefits e.g. EAD, gc etc. If you filed for EAD, you definitely need code 2 or the card can not be generated.

Code 1 expires after 15 months e.g. FBI needs to check their database again. I have had two code 1. Code 2 is done everytime we apply for benefits (EAD- once a year).
Code 3 is a combination of both, when USCIS wants to get a security check done on you as well as generate cards (EAD) for you.