MAC address is the unique serial number of your Network Card. It is SIX TWO-Digit HEX Numbers Separated by Column(:). By using MAC number You can Identify your Network Card Manufacturer.
By using the simple command ifconfig you can find your MAC Address.
Open a terminal and type ifconfig , you will get a text output. In the first line you can see likeHWaddr:00:BA:13:67:78:76.