By tapping the Apps option (under Device) in Settings, you can see all the apps installed on your device as well as those currently running. This screen will also show you how much space the apps take up on your device and how much storage you have remaining.
Tapping on an app will allow you to perform a ‘force stop’ (to close it down and save processing power) or uninstall it completely – it’s good to have a clear-out when new apps are downloaded and older ones are no longer used. If certain apps keep caches then you can also clear those on a specific app screen, as well as review the permissions that you have granted the app to carry out its functions. This is a useful place to come in order to get to know your device and your apps inside out.