Q: iTunes app stuck on loading

Go to the App Store updates tab. Try tapping on the circle to stop the download, then tap Update again. Try it a few times. If that doesn't work, go to Settings>Airplane Mode>On. That will disconnect you from your WiFi connection. Give it about 30 seconds and then Turn Airplane mode off. Try updating again.

You can also try a forced restart. No data is lost with this procedure. Hold down on the sleep and home buttons at the same time for about 10 seconds until the Apple logo appears on the screen.

If that doesn't work, and you can not find any other way to resolve this, try deleting the apps in Settings>General>Storage & iCloud Usage>Storage>Manage Storage. Let the list of apps load. Tap on the stuck app and then delete it in the next screen, then try downloading it again.