What is the UDID?(What is, Concept and Definition)

Abbreviation for Unique Device Identification , a UDID is a sequence of numbers assigned to each smartphone or tablet running the iOS operating system.UDID is a proprietary system that Apple uses to transfer information to and from iCloud and specific iPhone or iPad devices linked with the same Apple ID.

The UDID number of your iOS device is found in the iTunes program when connected to a computer with a USB cable.