When Account Only is selected you will be presented with two areas in the Data Entry section.
The Account Number area sets a custom label for the Account number field. This would be used if your bill has used a different label for the Account Number.
The Help Text area will allow you to place custom text that will assist your customers in finding the account number on their bill.
The Alias area sets up a custom label for the name 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.