The Data Entry Fields section allows you to customize the messages that will be presented to your customers when they are to enter data in the system.
The Invoice Number area allows you to set a custom label for the Invoice number field. This would be used if your bill has used a different label for the Invoice Number.
The Help Text area will allow you to place custom text that will assist your customers in finding the invoice number on your bill.
The Alias area allows you to set up a custom label for the name that the customer will use to describe their bill. It also allows you to set a different example as well as customized help text for your customers.