To find an invoice for a customer's order, go to the Orders tab on the left side, view orders, then search for the order you wish to find the invoice for.
Select the order number, which will open the order details page.
On the top left of the order details page, a View Invoice button displays below the order number and date.
Once you select view invoice, a PDF will open in your browser, in which you can view and download the invoice if needed.
For more details on customer's orders, go to the Orders section.
