To e-file, you just need an SSN or ITIN.
However, by filing jointly, you are required to report all your spouse's worldwide income and pay US tax on it. You can claim a credit or deduction for foreign taxes paid. If you file separately (MFS), you may pay higher US tax, but your spouse would not have to file a US tax return unless they had US-source income.
Filing MFS is often worse financially than filing MFJ, but you may need to test your specific circumstances.
