Define wording and layout of automated emails regarding payments and topups by going to Reports->Report Templates->System Email Templates

Within the Finance Tab of customer card you can setup if the customer is to be Prepaid and requires a balance to be available for them to send freight or if they may just have invoice charged to a credit card when they fall due

This is setup by going to Settings->General->Global Setup and navigating to the Website Widgets page, locate the Merchant Settings section and enter details for your merchant facility.

This can be used for customers to pay for freight prior to sending and is setup by making the customer card a Prepaid account

Customers can also be setup to have their invoices charged to a Credit Card when their invoices fall due