You do not send the ex any type of IRS Form for the alimony paid.
On your tax return you report the alimony paid, the Social Security number of the ex and the date of the original divorce or separation agreement.
This alimony payment and information is reported on IRS Form 1 Lines 19a, 19b and 19c. The alimony paid is an adjustment to income with the amount paid flowing to Form 1040 Line 10.
The ex is required to report the alimony received on their tax return. Failure to do so will result in the IRS sending a letter to the ex requesting payment of taxes on the alimony they failed to report on the return.
