Magic Leap 2

On Magic Leap 2, a device's MAC address can be found by opening the Settings app. Scroll down to "About device". On the screen that appears, you will see the "Wi-fi MAC Address" listed.

Magic Leap 1

On Magic Leap 1, the device MAC address can be found by navigating to Settings icon at the top of the display, Next open the Device icon, choose About from the left hand menu and then expand the Device Information section.  The MAC address will be listed on that screen.