A package system is a type of air conditioner where the components are all within the same unit.
This is a great option for when the desire is to only have one system rather than having an indoor and outdoor unit (split system). This means they are generally larger than other types of systems and are generally more ideal for commercial types of buildings. When installing a package type system a flat area is needed usually on a roof top but can also be designed to fit on an external wall or on the ground.
Ducting is then fitted to this system entering your home or building. This means that the only gear inside your ceiling is ducting distributing air. The finish from inside is the same as a ducted split system meaning grills and a wall controller is all you can see.
Other benefits is that due to the whole of the system being located outside there is no risk of any components causing damage with in your home or building if mechanical or electrical failure occurs with the system.