There is a new W-4 form for 2020. It doesn't use allowances anymore, so you no longer "claim 0" or any other number of allowances. The new form works differently. In January, use the IRS Tax Withholding Estimator at the link below to figure out what to put on your W-4 form to cover the tax on your alimony.
IRS Tax Withholding Estimator
