On Windows, open Command Prompt and run `ipconfig /all`
On Windows, open Settings > Network & Internet > Advanced network settings > Hardware and connection properties
On macOS, open System Settings > Network > select the connection > Details > Hardware
On macOS, open Terminal and run `ifconfig`
On Linux, open Terminal and run `ip link`
On Linux, open Terminal and run `ifconfig -a`
On Android, open Settings > About phone > Status > Wi‑Fi MAC address
On iPhone, open Settings > General > About > Wi‑Fi Address
On a router, check the device list or connected clients page in the admin panel
On a network adapter, check the label or device packaging
On a command line, look for the physical address, hardware address, or link/ether field