You can watch the video tutorial, which provides a step-by-step guide through the process.
You can print your invoices from both your Shopify store admin and Simple Invoice by following the simple steps below.
Shopify Store Admin
Step 1: Click on “Orders” in your Shopify store admin.
Step 2: Click on the order you wish to print, click on the ‘More Actions’ button, and click on the ‘Print with Simple Invoice’ option.
This action can also be completed from the Shopify Order Detail page.
Simple Invoice
Step 1: Open Simple Invoice from the “Apps” section of your Shopify store.
Step 2: Select the order you wish to print in the “Orders “section, click on ‘Print’, and select Invoice.