You will have to use the iOS over the air distribution. You can find various articles on the internet describing how you can do that. Here are three links that can help you:
I can see that you are not on a Telerik Platform paid subscription plan, but if you were, you could easily use the Telerik AppManager. It offers easy and secure app distribution outside of the public app stores, user management, app management and more. All paid subscriptions have access to the Telerik AppManager. You can read more about it here
I hope this information was helpful. Do not hesitate to ask should you have any other questions.