If your spouse does not have a Social Security number or an ITIN, then you can only file your tax return as Married Filing Separately. The return will have to be printed and mailed, it cannot be e-filed. You will have to write in the box for your spouse's Social Security number NRA, for non-resident alien.
See this IRS website for information on obtaining an ITIN - https://www.irs.gov/individuals/individual-taxpayer-identification-number-itin
