The Preferences section can be found in the left menu under the Account section. Preferences is essentially the 'brains' of your BillingOrchard account and any changes made in this section will affect your system globally (system-wide).
As viewed below, there are a large amount of options available / changes that can be made through the Preferences section. Viewing the screen shots and video accompaniment below will give you a better understanding of this section and what its capabilities are.
This video will outline some of the features found in the Preferences section: