Simple Invoice just prints your order data as an invoice. Once you have your taxes set up correctly in your Shopify store, Simple Invoice will use these tax settings and automatically display all the required tax details on your invoices.

There isn’t any configuration needed on the Simple Invoice side.

You can find some key points about why your taxes are not printed on your invoices:

• Do you mark your products as “taxable”? If you didn’t do that, for proper taxation, please check the “Charge tax on this product” checkbox for your products.
• Did you set tax rates for each country you make sales in properly?
• And It might happen sometimes that a customer was accidentally set as “tax-exempt” when they should not have been. Please also check the customer settings for your customers.

Please be aware that if you make any changes in tax settings in your Shopify admin, only your newly created orders and invoices will reflect this change. Your existing invoices will remain unchanged.

You can find more information about setting up taxes on the Shopify side by clicking here.