An order represents an agreement/request to be made, supplied or served between two entities. An entity can be either a person or a company. Each order can contain one or more line items. Each line item has a unique price, quantity and description that it stores. The order total is generated by the collection of line items making up that order.
An order can be used for a multitude of processes in the system. It can serve as the basis for assessment between a company or organization and a person. It can be used as a means of assessing fees for a student who is enrolling in one or more classes. The order can also represent a solicitation to request that a current association member renew their dues for a subsequent year. There are many applications. The order itself is essentially what happens in a retail environment when you purchase items from the store. An invoice or receipt is simply the printed version of the order showing its current status and current amount due.