Media Access Control (MAC) address is also known as hardware address/ physical address which is is a unique value associated with a network adapter. MAC addresses are 12-digit hexadecimal numbers ((0-9, plus A-F, capitalized) 48 bits in length, in order to make it easier to read most often it is written with a colon or hyphen separating every two digits, The ID number of the adapter manufacturer is present in the first 24 bits of a MAC address as assigned by the IEEE. 

As we all know, your WiFi network's signal doesn't end at your walls. That's why the need for WiFi security was born. Anyone can access your WiFi signal if it is near your home or office. Wi-Fi security stops unauthorized users from using your network and accessing any of your data.