US versions only....
Item sales taxes are used to track sales tax payable for separate taxing authorities.
To create an Item Sales Tax, click Lists --> Profile Lists --> Item Sales Tax. Enter a short Name and Sub Item (if applicable), the tax percentage, description and tax authority (vendor) then click Save, Save & Close or Save & New.
You can set the default item sales tax for a customer.
If an item or customer is taxable (i.e. when 'Sales tax code is a taxable' is checked), then All Orders will use the Item Sales Tax rate to determine the tax on quotes, sales orders and ship docs.