You can visit https://portal.taxicaller.net/dispatch/notifications and go to the third tab called receipts and you will see a first chart with Field Value in the top. The Field is the type of information you can edit in the receipt and the value is the information that will contain that label.
In the second chart you can see three columns Custom, Label and Value. This is quite similar as the first chart but here you can customize your labels to show other important information you might want the customer to see.
(suggested by Jean)