You can create packing slips from the Orders section by following the simple steps below.
Step 1: Open Simple Invoice from your Shopify store’s “Apps” section.
Step 2: Select the order you wish to create a packing slip, select print, download, or upload, and select the Packing Slip option from the dropdown menu.
Important Note: You can only print, download, or upload documents. It is not possible to do directly send Packing Slip. You can manually download and send it to your customer.
You can also customize the Packing Slip template from the Templates section.
In order to customize the template, Click on the Templates and select the Packing Slip from the Template Type dropdown menu.
After you make the necessary changes, Click on the Save button.