Finding your iPhone, iPod touch or iPad’s unique ID (UDID)
Every iPhone, iPod touch and iPad has a unique identifier number associated with it, known as a UDID (Unique Device ID).
Your UDID is a 40-digit sequence of letters and numbers that looks like this: 0e83ff56a12a9cf0c7290cbb08ab6752181fb54b.
It’s common for developers to ask for your UDID as they require it to give you beta copies of iOS apps.
Finding your UDID using iTunes
Open iTunes (the Mac or PC app, not iTunes on your iPhone).
Plug in your iPhone, iPod touch or iPad.
Click its name under the devices list.
Ensure you’re on the Summary tab.
Click on the text that says Serial Number. It should change to say Identifier (UDID).
Select Copy from the Edit menu.
Your UDID is now in the clipboard, so you can paste it into an email or message.