As a Shopify store owner, you might sell raw materials or products to other business owners. When selling to another business, you may need to generate PDF invoices so your clients have the relevant details of their order. PDF Invoice apps allow you to issue printable invoices via email to your customers after an order. These apps have ready-to-use templates that you can choose from, such as order, refund, and packing slip templates, which you can customize with the order details and your company information. Some apps even allow you to convert the invoice into your customer’s local language and currency and automate post-order invoice emails.