iOS Deployment Overview
From Xojo Documentation
There are several ways to deploy iOS apps to devices, which are briefly outlined below.
Ad-Hoc Deployment to Devices
With Ad-Hoc Deployment, you build your iOS apps using an iOS Development Profile and manually copy the built app to the device. To create this profile you need to be a member of the Apple Developer Program (currently $99/year from Apple) or you can use the free provision profile provided by Apple. You can deploy apps built in this manner on up to 100 devices.
For details on the steps to do this, refer to the sections Ad-Hoc Device Deployment and Free Provisioning Profile.
For beta testing purposes, you can also use Apple's TestFlight server to allow up to 1000 users to install a beta version of your app. Use of TestFlight requires that you are a member of the Apple Developer Program.
For details on the steps for using TestFlight, refer to the section Using TestFlight.
To get your app in the hands of end users, you will typically want to use the App Store. To do so, you will build your app using an iOS Distribution Profile. You will have to be a member of the Apple Developer Program.
For details on the steps to submit to to the App Store, refer to the section Submitting to the App Store.
Volume Purchase Program
The Volume Purchase Program provides a way for you to distribute apps to businesses or educational institutions without having to publish your app to the App Store.
Businesses can use the iOS Developer Enterprise Program to get tools and resources for developing proprietary, in-house iOS apps that you can distribute to your employees. These apps are distributed outside of the App Store.
For more information, visit Apple's iOS Developer Enterprise Program page.