You see these fields in the History tab of the Customer Maintenance dialog box:

Open Credit: This field displays the customer's open credit balance, which is the total of all payments that have not been applied to any of this customer's invoices. Accounts Receivable maintains this amount.
On Order: This field displays the total price of orders that have been entered but not yet shipped. Factory Orders updates this amount.
YTD Sales: Displays the dollar value of merchandise this customer purchased during the current year. When you close the year, this amount moves to the history file, and the field resets to zero. Note: the only time you can enter a value in this field is when you are adding a new customer. After you save the customer record, the program maintains this value.
Entry Date: This field displays the date that you created this record. The program automatically enters the current system date.
Last Sales Amount: This field displays the dollar value of the last order shipped to this customer.
Last Sales Date: This field displays the date of your last order shipped to this customer.
Last Payment Amount: This field displays the dollar value of this customer's last payment.
Last Payment Date: This field displays the date of this customer's last payment.