You use a purchase order to tell a vendor that you want to order
goods or services.
Purchase orders help you keep track of what you have ordered and
what you have already received. When you have received everything
on the purchase order, QuickBooks marks the purchase order
"Received in full."
When you receive the goods or services, QuickBooks uses
information on the purchase order to enter a bill, check, or credit
card charge for the same vendor.
When you use purchase orders to order inventory items, you can
see not only how many items are in stock but how many are on order
and when they're due to be received.
You can also use purchase orders to order services from a
contractor, office supplies, a new asset for your company, or other
items that are not set up as inventory in QuickBooks.