If the reason for deleting this app is because you don’t want others to open it, please know that you can protect this app with its free Child Lock feature.
To delete this app anyway, close the app and go back to your device's home screen. Locate the app's icon, tap and hold it until all apps start to wobble. Then tap the X that's on the app's icon to delete the app.
You can always get the app back from the App Store: https://itunes.apple.com/app/id871132166