I was divorced 3 years prior to obtain resident alien. I have been paying alimony and my children live with her. Now, working abroad, how can I file tax e-filing, without her ssn while paying alimony?

Thanks,

-jk

Without your ex-spouse's SSN, you CANNOT efile.

You CAN file a paper return by putting NRA (for Non-Resident Alien) where her SSN would go. However, if you pay alimony to a non-resident alien spouse, you will probably HAVE to withhold 30% of the alimony and send it to the IRS, because alimony received is considered to be taxable income to your wife.