Alimony, just like child support, is tax free income. A support payer must pay income taxes on the money paid toward support. The support recipient does not need to report the support payments as income.
In cases where the divorce was resolved prior to December 31, 2018, the parties could choose for the receiving spouse to report the alimony as income and pay the taxes on it and for the paying spouse to deduct their alimony payments from their taxable income. The choice is no longer available for cases filed after January 1, 2019 but any alimony modifications in those older cases, allows the parties to still choose.