You should be able to pay with Pay1040.com, but they charge a fee. You can also mail a check (in U.S. dollars) with Form 1040-V payment voucher. (Checks are mailed to a different address and will be processed promptly.)
If you mail a check, make it payable to "United
States Treasury." On the check write "Amended 2019 Form 1040-NR" and your Social Security number or ITIN. Mail the check and Form 1040-V to the following address.
Internal Revenue Service
PO Box 1303
Charlotte, NC 28201-1303
USA
