Work order: what it is, types, and the process 

A work order is an internal document that authorizes and details a specific piece of work. In manufacturing, it is the instruction to produce a set quantity of a product. It matters because it is what turns a production plan into actual work on the floor: it tells the team what to build, from which components, and by when, and it is how you track that build through to finished goods.

Across several products and production runs, work orders are the record that keeps production, inventory, and costing lined up. This guide tells you what goes on a work order, how it moves from created to closed, and how it differs from a purchase order.

The focus here is on manufacturing, or production, work orders, because that is the one that drives inventory, which consumes components and produces finished goods. In every setting, a work order turns an instruction into a traced task, with someone responsible for it and a deadline to hit.

What goes on a work order? 

A production work order carries the details the floor needs to build and the office needs to track:

• Work order number: A unique reference for the build.

• Product and quantity: What to make and how many.

• Components and materials: What the build consumes, taken from the bill of materials.

• Operations or routing: The steps and machines involved.

• Schedule: Start date, due date, and priority.

• Resources, instructions, and status: Who is assigned, any special notes, and where the build currently stands.

Types of work order 

The same word covers several job types, and only one of them is really about inventory:

• Production work order: Make or assemble a quantity of a product. This is the inventory-relevant one, and that is the focus here.
   

• Maintenance work order (also called a service order): Repair or service equipment.
   

• Inspection or emergency work order: Check or urgently fix something.

The work order process (lifecycle) 

A production work order moves through a handful of stages, and stock changes at each:

• Created: The order is raised, often from a sales order or a demand plan, listing the product, quantity, and components.
   

• Released: It is approved and sent to the floor, and the components it needs are reserved.
   

• In progress: The build happens, and components are consumed and logged against the order.
   

• Completed: The finished goods are received into stock.
   

• Closed: Actual costs and quantities are reconciled against the plan.

Following the order through these stages is what keeps your component and finished-goods counts accurate.

Work order vs. purchase order 

Work orders and purchase orders are easy to confuse, but they point in opposite directions: a work order authorizes work inside your operation, while a purchase order buys goods from a supplier outside it.

The purchase order also serves as the contract with the supplier, while the work order stays an internal instruction to your own team.

How work orders connect to BOM and MRP 

A work order does not stand on its own. Its components list comes from the bill of materials, which defines what goes into the product. In a planning system, material requirements planning (MRP) works out what needs making, then releases those planned builds as work orders. The bill of materials defines what a build consumes, MRP decides when to build it, and the work order carries that instruction to the floor.