When you go to your "Customers" tab and open any customer from there, you can see the general overview of this customer's information. If you take a look on the right side, there is a "Customer balance" section.
How is customer balance calculated?
Customer balance section shows an overview of unpaid invoices linked to this customer and also customer prepayments. This means that when an invoice for this customer is created, it shows in the customer balance section:
When the customer makes a prepayment which is linked to this customer, this will also show up in the balance section:
Note: Customer whose name is in the policy info does not necessarily have to be the invoice recipient. Therefore, unpaid policy installments are not shown in the customer balance section - you need to generate an invoice and link it to the specific customer first!