Thank you so much for help. I do not have income from US source at all. If I don't need to file 1040NR, then should I file 1040 for the last 1 full year, or only partial year of the US citizenship? If I need to file for the partial year, can I use the standard reduction?
Still, I have a question regarding this matter. I also got advice form other tax expert.
"U.S. tax residency – Green card test. You are a resident, for U.S. federal tax purposes, if you are a lawful permanent resident of the United States at any time during the calendar year."
https://www.irs.gov/individuals/international-taxpayers/us-tax-residency-green-card-test
He said this applys to the US citizenship also, so he advised me I need to file 1 full last year as a resident.
I would appreciate it if you could help me clarify this.
Thank you again.
