When youâ€™re not connected to WiFi, your phone will periodically send out a signal for WiFi networks in the area to help you get connected. That signal will contain the unique physical hardware address for your device. Some places, for example shopping centres, supermarkets or other public areas, might use this unique address to track your movement in that area. If your WiFi hardware (ex: Lumia 950 and 950 XL) supports it, you can turn on random hardware addresses to make it harder for people to track where you go for any network.
You can use random hardware address for any Wi-Fi network. After you connect to a Wi-Fi network, you can then determine if you want to use a random hardware address for that specific network.
This tutorial will show you how to turn on or off to use random hardware addresses (MAC) for Wi-Fi networks on your Windows 10 Mobile phone.