Here you can find instructions on how to find out the UDID of an iOS device.
Windows
The UDID cannot be found out directly on the iPhone. You need a computer with iTunes.
- Connect your iOS device via USB cable to your computer and start iTunes.
- Click on your iPhone in the upper right corner, and you will get to the overview. Above on the left side you can see the data like battery level, storage capacity, phone number and the serial number.
- Click on "Serial number" and the UDID will be displayed.
- You can copy the UDID from iTunes by right-clicking on it.
Mac
- Connect your iPhone to your Mac with a USB cable.
- Open the Finder.
- Select iPhone.
- Click on the General tab.
- Click on the text that appears under your device name.