Actually, iOS MDM is purely server technology. Meaning that MDM client is integrated in iOS. What you may have seen are some MDM boostratp applications which are installed on iOS device. However, all they do are triggering device configuration (installation of MDM config profile).
However, as part of the MDM protocol, you can get UDID of device (using DeviceInformation command). However, you can get it on the server (not in your iOS app).