You can turn on automatic invoicing on the settings page. But you can also exclude order types from being invoiced automatically.
On the orders page on the left you will see a shortcut To Invoice (-), when you have excluded order types to be invoiced after the date and time of delivery for the order you will be able to easily see the orders which need to be invoiced. This feature can be used for events where you need to work out the final invoice amount after the event has finished.
This feature is available from the standard plan up and the production, distribution and catering editions.