About managing taxable and nontaxable items
You can have an order with both taxable and nontaxable items. If the entire order is tax exempt, then define the order as tax exempt at the header level, then all of the lines are exempt. Typically, this information is derived from the customer or ship to address. If, however, you define the order as taxable at the header level, then you can define individual order lines as either taxable or tax exempt.