Shopify has 3 fields that you can use when mapping tax information with your order:
- tax_included - This field indicates whether or not taxes are included in the order subtotal. Valid options are True or False.
- total_tax - This field is the sum of all taxes applied to the order. Shopify does not provide taxes at the line item level so this should be the total tax for the order.
- taxable - This field states whether or not the product was taxable. Valid values are True or False.
Make sure your item price does does not include the tax value. If the item price does include the taxes then you'll need to set tax_included to True for Shopify to import this correctly.