You can use both invoice numbers and order numbers at the same time by following the simple steps below.

Step 1: Open Simple Invoice from your Shopify store’s “Apps” section.

Step 2: Click on the “Templates” on the Simple Invoice dashboard.

Step 3: Click on the Options section, and click on the Show Order Number under the Order Details.

Step 4: Click on the Other Settings section, and click on the Show Custom Invoice Number.

Important Note: If you do not click on the Show Custom Invoice Number and set your Prefix and Start Number, the Custom Invoice Number will be printed under the Order No by replacing the Shopify Order Number.

If you only want to show the Custom Invoice Number, you can simply uncheck the Show Order Number option.

You can also change the title of both Order No and Invoice No simply by clicking on them since all text fields are inline editable.

Step 5: Click on the Save button.