UDID is an abbreviation for Unique Device Identifier. The UDID is a feature provided by Apple to identify iOS devices. Apple uses the UDID to communicate between Apple servers and individual iOS devices. This allows Apple to associate the Apple ID and the Cloud ID with the corresponding iOS device. Each iOS device has an unique ID.

The UDID of your iOS devices is needed if you want to install alpha and beta iOS apps onto your device before they are released to the official apple store.

1. Click "Accept" to fetching the profile file.
2. Open installed Profile.
   1. iOS: Open "Setting.app" -> "Downloaded profile" -> "Fetch device's UDID" -> Install.
   2. macOS: Open the profile named install.mobileconfig then open "System Settings" and click "Profile" in left sidebar menu.
3. After install it will open Safari and redirect a result page then delete the profile automatically.