Work order vs purchase order
A work order authorizes a service job; a purchase order authorizes a purchase of goods or services from a supplier. If you run a service business, the work order is the document your customer signs before the crew starts. It is not an invoice, and it does not replace the contract for a larger project.
Write a scope you can point to
List the tasks included, the site or unit, and the access arrangements. Then add one line that says what is not included. When the customer asks for “one more thing” on site, the scope line is the difference between a change order and an argument.
The authorized total
Put a number on the work the customer is approving. If the job is time and materials, state the rate and the estimate, and say that the total may change if the scope changes. For a fixed price, the authorized total is the number the customer agreed to — anything beyond it needs a new approval, in writing.
Change orders
When the scope changes, do not quietly add it to the invoice. Write a short change order — or a new work order — with the extra work and price, and get it signed before the work continues. It protects the customer from surprises and protects you from doing unpaid work.
Close the job
Get the signed work order, the site photos and the invoice into one folder. If the invoice is queried, the signed authorization is the first thing to send. For the billing document, use the blank invoice template or the online invoice generator.