The device's MAC address isn't available under iOS 7 and later

For privacy reasons, Apple has removed all the possibilities to uniquely identify iOS devices and users. In iOS 6 the UDID unique identification number was removed and starting with iOS 7, the MAC address access was removed too as it is also unique and could be used to track users. For this reason, MAC address isn't shown for the device on which Network Analyzer runs.

You can find the MAC address in iOS settings under Settings->General->About.