For 2021, it sounds like you are eligible to be considered a non-resident alien, because you don’t meet the substantial presence test.
https://www.irs.gov/individuals/international-taxpayers/substantial-presence-test
In that case, you have the option to file married filing separately. If your spouse files as married filing separately, then you would file a nonresident tax return and you would only report US-source income. If you don’t have US sourced income, you don’t need to file a US tax return at all and you don’t need an ITIN.
If you want to file as married filing jointly, then you are making an election to be treated as a US resident for the entire year, and that means that you must report and pay US tax on all your worldwide income. If you also pay tax on the same income to a foreign country, you can claim a deduction or credit for those taxes on your US tax return. No one here can tell you whether, in your particular situation, it would be more beneficial to file separately or jointly. That is something you would have to work out for yourselves or with the help of an international tax expert.
If you decide to file jointly, then you can’t apply for an ITIN separately. The only way to apply for an ITIN it is to print the form W-7 application and mail it, along with a printed and signed tax return and any proofs required by the W-7, to the processing address in the W7 instructions. After the IRS issues the ITIN, they will forward your tax return for processing. You can’t e-file this year.
You will probably need to use a fake ITIN to allow TurboTax to pass its error checks and print your return. You can try 999-88-9999. Be sure to cover the fake ITIN with some white out before you mail the tax return.
Don’t file your state tax return when you file your federal return. Wait until the IRS issues the ITIN, then go back into TurboTax, change the fake number to the real ITIN, and then print, sign, and mail your state tax return. You may need to apply for an extension of the state tax return deadline.
