After you're married on a K-1 visa, you apply to Register Permanent Residence or Adjust Status?

Question

And when would be the right time to apply for a work permit?

Answer 1

After marrying, an "Adjustment of Status" (using a USCIS form I-485[2]) must be filed that will convert the K-1 fiancé(e) and K-2 children status to that of "Conditional Lawful Permanent Resident Status", e.g., a green card. It can take as long as a year after the filing of a correct I-485 to be invited to a local USCIS Office for an interview of the Petitioner, K-1 fiancé(e), and any K2 children. The interviewer is essentially interested in ascertaining if the marriage is legitimate, and will ask questions a genuine couple should have no issue answering, for example, "Who normally does the grocery shopping?", "What night does the garbage go out?", "When was the last time your spouse took the day off work?". I

     f the interview goes well, the I-551 "green card" will arrive in the mail in a few weeks - although post September 11, this time has been increased due to a backlog in CIA processing of background checks. If the Petitioner or the fiancé(e) does not attend the Interview, the fiancé(e) will lose legal status and must leave the US.

also a work authorization card (EAD) is occasionally issued at the port of entry (although more and more rarely, but can be obtained before the green card is in hand, the usual process being to apply  with the Adjustment of Status document