If you file as married filing jointly, you must treat her as a US resident for tax purposes and report and pay US tax in all her world-wide income.
If you file as married filing separately, you don’t need her tax number and you don’t include her income, but you can’t e-file. Print your return, write “NRA” in the space for her tax number (non-resident alien) and mail your return. You may need to use a fake SSN to bypass the error check. Try 999-88-9999 and then use some white-out to cover it on the printed return.
Filing by mail is also the only way to obtain the 2 month extension for overseas taxpayers unless you already requested the 6 month extension online.
https://www.irs.gov/individuals/international-taxpayers/us-citizens-and-resident-aliens-abroad-autom...
