When you first get your iPad or iPhone, it comes with several applications already on it. But that is not all you can use it for. The app store has thousands and thousands of apps that you can add to your device. There are two main ways to add apps, the iTunes store and the App Store on your device.
The multi-task bar on your iPad, iPhone, and iPod touch allows you to access all the applications the running on your device. It allows you to shut down applications, jump to other applications, access your music player controls, and so on.