There are two types of orders - prepaid and postpaid. In a prepaid order, you pay for the service before it is provided; in a postpaid order, you pay for it afterwards.
The type of order depends on the terms of payment for the service. You can see this information in the catalog or on the Service home page.
The payment type is selected by the supplier when the service is added to the marketplace, so you as a buyer cannot choose between postpaid and prepaid. If payment terms are important to you, be sure to review them before booking a service.
Prepaid and postpaid orders consist of the same steps, but the order and some details are different.