Tony Carter says:
You can start the process anywhere, but let’s do a brief overview of the K1 visa steps so you can piece together in your head the flow and logistics.
The first stage is called the USCIS stage, and that’s where you’re going to submit your initial petition, that’s the I-129f form with supporting documents. That’s mailed to the USCIS. You have to mail it to a lock box that’s designated, usually based off your U.S. citizen’s fiancee’s address. Once it gets to a processing center, they take anywhere from 5 to 6 months (or longer) to review it, and make sure that you have a legitimate, bona fide relationship, and that you’re eligible for the benefit that you’re applying for.
Next, they will forward your petition on to the National Visa Center. And at the National Visa Center they assign a NVC, case number. And then send it on to the embassy in the U.K.
Once the case is at the embassy phase in the U.K., you will be in contact with them, and more will happen locally for you.
But to get the ball rolling on your RapidVisa account, you can start right now by creating your free fiance visa account, and answering the alien questions for your section now. This will give your fiance less time to bug you for answers later. You can also get started searching for any documents you might need later on that could take awhile obtaining. Birth certificate, passport, old divorce decrees, etc. By getting these now, you will have them later when you need them. Be sure to check the expiration dates on these items though, because some of them may be worth getting closer to your interview date if they have an expiration date.