Withholding tax is not required in SAP but this functionality available for the countries where it is required. There are two kinds of Withholding tax, Classic and Extended.

The income tax is what is paid by "withholding of tax" from someones payment/pay. Other taxes or charges, like insurance, worker comp, etc may be [apd by withholding the amount from payment/payroll. There is really no such thing as a tax on withholding.

yes

Classic Withholding Tax applies to the practice in some countries for people paying invoices to hold back a certain portion of their payment for withholding tax purposes. The United Kingdom is one of the countries the utilizes the Classic Withholding tax method.

16. The Thurstons' total federal income tax withholding is $