You can learn how to add your logo to pro forma invoices.
1. Open Easy Invoice+ from Apps section of your Shopify store or go directly to https://easyinvoice.softify.co/
2. Click “Pro Forma Invoices” from left menu.
3. Edit your existing Pro Forma Invoice or create new one.
4. Click “Choose File” from left settings panel of Pro Forma Invoice template and choose your logo from your computer.
5. Click “Save” button.
Suggested logo size is 250×100 pixels but Easy Invoice+ can also auto resize your logo to your Pro Forma Invoice template.