Alimony
You can deduct alimony you pay to a former spouse as long as the monetary payments are spelled out in your divorce agreement. You must report your ex-spouse’s Social Security number, so the IRS can make sure he or she reports the same amount as taxable income. (Child support, however, is not deductible.)
The new tax law eliminates this deduction for agreements signed after December 31, 2018. For agreements signed before then, the deduction continues.