You can make permanent changes to your invoice template by visiting the “Customize Template” section of Simple Invoice. Once you finish making changes to your invoice template, it will be automatically applied to all your orders.
Step 1: Click to the “Apps” section of your Shopify store and click on Simple Invoice.
Step 2: Simple Invoice will automatically redirect you to the orders page.
Step 3: Click on the “Dashboard” from the upper left corner.
Step 4: Now you should see the dashboard of Simple Invoice. Click on the “Customize Templates” section.
Step 5: Now you can make the changes to your invoice template and save it from the upper right corner.