Login to your WordPress Admin Area and click on FooSales > Settings in the sidebar menu.
You can change the wording and/or translate the following text in your printed receipts and invoices at present:
Receipt title
Order number prefix
Product column title
Quantity column title
Price column title
Subtotal column title
“Inclusive” abbreviation
“Exclusive” abbreviation
Discounts title
Refunds title
Tax title
Total title
Payment Method title
Billing Address title
Shipping Address title