Your device - be it a computer, a tablet, or a phone - can connect to the Internet because it has a NIC.
So a MAC address - I’ll call it MAC from now on for short - is precisely that, the unique identifier to control the access of a network interface controller (NIC), which we often call a network adapter. How to change the MAC address of a Mac computer.How to change the MAC address of a Windows computer.How to change the MAC address of a router.Reasons you might want to change your MAC.
