Here is a full Video Guide & Photo Guide to get Kodi on your iPhone or iPad without a Jailbreak
Video Guide followed by Photo guide below
Go to this website and choose to download Kodi 16.1 or Kodi 17.0 (18 is unstable)
Wait for it to load then click on it
The App then needs trusting so click cancel
Go to Settings then General then Device Management
Click on CVT MEDIA
Click on Trust 'CVT....'
Go Back to the Kodi App and it will work
PLEASE NOTE: If you get a blank screen exit the app then close it by double clicking home button then go back into and it should work fine. You are also doing this at your own risk.