What is the document I fill out to start k1 process for my Mongolese fiance? We both live in niigata japan.?

To file forms for the K-1 fiancé visa for a foreign fiancé, you must be a US citizen.You must earn enough to meet support requirements AND have a suitable home for you & your fiancé/spouse in the US (not living with parents or some such). You will need your current year paystubs + last 3 years of US income tax returns to prove earnings for the Affidavit of Support.

Apparently, you have been living outside US for a while? You MUST have filed your US income tax returns while you were living, working outside the US? You might not have owed any income taxes if you were eligible for Foreign Earned Income Exclusion and/or tax credits for taxes paid to Japan under any double taxation agreement, but you still had to file! Make sure you have all those returns properly filed or else you need to hire a tax accountant URGENTLY, and settle up with IRS first.

You are going to have to return to US, get a job earning enough to meet support requirements (and work there a minimum of 6 months before you file for K-1), and get a place suitable for the 2 of you to live. Your fiancé cannot enter the US until approved for & receives the K-1 visa. Your fiancé will be interviewed, etc, at the nearest US consulate to his/her home. Expect it to take about a year from the time you file for the K-1.

If you are going to continue living & working in Japan, you do NOT file for a K-1 visa. It's for US citizens residing in US who want to bring their foreign fiancé into us, marry in US & reside in US. Which is why you need a suitable home in US.

Have you filed taxes with the IRS for the last 3 years?

Do you have a job to return to earning enough money back in the US to sponsor this person?

If the answer to those two questions is no, then you will not be sponsoring a K1 and they will not be migrating to the US