Work Orders are fundamentally in house Purchase Orders. They are for producing finished goods that are being sold and/or stocked in inventory. The term "Work Order" is used in countless different ways, but our basic definition is "an order for production".
In BusinessMaster, Work Orders are used only for production based manufacturing. The Work Order Manager is designed to allow you to release Work Orders quickly and accurately to your production floor. Use Work Orders for things that are production oriented, BOM based, Part Number based, and/or where you are making real consistent widget types of things. This is opposed to custom manufacturing, when the things you build are different from job to job. Custom manufacturers are going to primarily want to use the Projects module. Work Orders are basically a handy way to do rapid production in response to current or expected demand.
This is a screenshot of the Work Order Manager:
