After creating a tax class, you can assign it to products. Any products with a set tax class will use the tax rates defined for this product class.
To assign a tax class to a product:
In the Catalog -> Products section of your X-Cart Admin area, choose a product to which you need to assign a tax class and open this product's details page for editing.
In the Prices & Inventory section of the product details page, locate the Tax class field and select the tax class you want to assign to this product.
Click Update product to save the changes.
The tax class is assigned.
If you need to assign a tax class to more than one product, you may find it convenient to use the "Bulk Product Edit" feature.