Filling back orders
If you attempt to record an invoice and you don't have enough items to complete the sale, you'll be given the option to create a back order for those items. When the items arrive and you're ready to send them on to the customer, display the Sales window and select the customer. A list of open quotes and orders for the customer -- including the back order you recorded -- will appear. Highlight the back order and click the Use Sale button to display the back order in the Sales window. Click the Change to Invoice button, and make any needed changes to the invoice that appears, then record it.