You can save PDF documents for yourself in Order Printer Pro, in a couple of ways:
Export a PDF for a single order
In your Shopify admin
Go to the Orders section
Click on an order to open it
In the "More actions" dropdown, select Export PDF with Order Printer Pro
Export PDFs for multiple orders
In your Shopify Admin
Go to the Orders section
Put a checkmark on the orders you want to export as PDFs
In the actions bar, click on the three dots, select Export PDFs with Order Printer Pro
Note: You can select and export a maximum of 50 orders at a time. The 50 order limit is something that Shopify controls, and apps unfortunately cannot change that limit.