A MAC address (media access control address) is a unique identifier assigned to network interfaces for communications on the physical network segment. Every computer device have different MAC address. The MAC address is a built-in every computer device when it is created. When computer starts, operation system reads from hardware device. When you are connected to the wireless network, it sends packets to you and then your computer converts these information to websites, movies, images… Imagine that two computers are connected to the wireless network, first computer wants website google.com, and the second computer wants amazon.com, network sends packets to these computers, but how do these computers know what packets ignore and what packets to recive? Computers identify packets to recive or ignore by MAC address, when the network is sending packet to computer, it also writes in packet the MAC address of the computer it is sending. that is the way how wireless networks and computers are connecting each other. So, if you do not change your ip and hack someones wireless network, you let them to investigate your identify by analysing network history.
How to hide MAC address?
You may think that how you can change MAC address if computer reads it from hardware? You are not going to make modification on hardware, you going to change RAM. When the computer starts, MAC address loads in RAM and we going to change already loaded MAC address.. So, when you change your MAC address police will find your fake MAC address and they will not be able to trace hacker. Now you have basic information about what is MAC address, dangers of hacking without changing MAC address, how police can trace you, how we can change it.