Sometimes you need to send UDIDs of your customers' devices to your e-mail address.
You may use get.udid.io for such purpose in the way described further.
https://get.udid.io/[email protected]&uid=john appleseed
When user passes UDID retrieval process by that link and press "Send UDID via E-mail", Mail application will start and pre-composed message, containing UDID and User ID (any string you will provide in 'uid' optional field) will appear.
Your customer should tap "Send" button to send e-mail containing UDID of his device.