Is the primary taxpayer a US citizen or green card holder?
If no, then you only file a US tax return if you have US-sourced income. You would file a 1040-NR, and you can't file jointly. Turbotax can't prepare a 1040-NR, you need another software provider.
If yes, then you have two options.
1. File as married filing separately. Your spouse does not need a tax number, but you can't e-file. (And your spouse won't be assigned a tax number even if you apply.) Use a fake number like 999-88-9999 to get Turbotax to allow you to finish your return and print it. Then, erase the fake tax number or cover it with white-out, and write "NRA" in the box for your spouse's name on page 1 of form 1040. Sign and mail the return, you may want to use a service with tracking and proof of delivery.
2. File as married filing jointly. In this case, you make an election (choice) to treat your wife as a US resident for tax purposes. This means that you must report and pay US income tax on all her world-wide income, including income that is already taxed in her home country (the US will allow a deduction or credit against the foreign taxes). While MFS has higher tax rates and some tax provisions are reduced or limited, the requirement to declare your spouse's foreign income may make filing MFJ less attractive, only you can tell based on your particular circumstances.
To file and obtain a tax number, you again need a fake tax number to get Turbotax to work, and you still can't e-file. Cover up the fake SSN and write "TIN applied for". Your spouse must also download, print and sign a form W-7, application for ITIN. Read the instructions carefully. Mail the tax return, the completed W-7, and any required documentation, to the IRS address for ITIN applications, not the normal address for tax returns. After the IRS issues the ITIN, they will process the tax return.
