Married taxpayers usually file jointly or separately. If your spouse is a nonresident alien, you can file as Head of Household which might increase your refund. To qualify, you need a qualifying person other than your spouse. Here’s a link with a list of qualifying relatives. Here is a TurboTax Help Article explaining this unique exception.
You should apply for a Taxpayer Identification Number (TIN) by attaching Form W-7 to the front of your tax return when you mail it to the IRS. Leave the SSN field for your spouse blank on Form 1040, so the IRS can fill it in after assigning the TIN.
Here is a link to the TIN application process.
