How To: Create printable invoice for specific order

To create invoice for specific order you should make the following:

Specify invoice template to use for product listed in this order. This could be done using product editing dialog.
On main form locate needed order and click in menu Orders | Generate Invoice or press CTRL+G on keyboard.
Specify file name where to save generated invoice.
After these steps invoice will be generated and you can use your favorite editor for printing or editing it.