What is the difference?
In Buildxact we treat purchase orders as expenses from outside the business, for example supplier invoices or contractor invoices. On the other hand, we use work orders for internal costs, for example entering time sheets. The main reason for this distinction is when connecting with accounting software, where purchase orders sync to your accounting and work orders do not.
Even if you're not connecting to an accounting system, we still recommend making the distinction between the types of orders for easier tracking.