For example, in a business process that handles purchases, each work item could be an individual purchase order. There can be any number of work items traversing a business process, just as there can be any number of purchase orders going through a purchase order system.
Every work item has a specific history and properties. For example, a purchase order usually contains a customer name, a list of items, an amount due, dates of delivery and payment, and other required data. A work item can also have various status conditions. In the case of a purchase order, you want to know if it has been approved, billed, or paid, or if the requested products have been shipped.
The life of each work item has a beginning and an end, as defined in the business process. As the work item proceeds through each step of the process, it is worked on by human participants or processed automatically by software.