Are you asking for the address on where to mail the federal tax return, Form 1040, from international?
https://www.irs.gov/filing/where-to-file-paper-tax-returns-with-or-without-a-payment
This is the address to mail if you are not including a payment -
Department of the Treasury
Internal Revenue Service
Austin, TX 73301-0215
USA
This is the address to mail if you are including a payment -
Internal Revenue Service
P.O. Box 1303
Charlotte, NC 28201-1303
USA