App Store
Screenshots come from iOS 9.2 on an iPad Air. Some features may be different for each OS, device, and country. To see which OS your running go to Settings > General > About.
The App Store is where you can download over 1,400,000+ apps for iPad, iPhone, iPod Touch. Anyone can create an app and submit it to the App Store to be able to do this all you need is Xcode and a iTunes Connect account.