Full answer
A WiFi router receives internet data through a physical cable (from your ISP), then converts it into radio wave signals. These signals radiate outward in all directions — your phone, laptop, or smart TV has a wireless adapter that catches them.
The two main frequencies are 2.4 GHz and 5 GHz. The 2.4 GHz band travels farther and penetrates walls better but is slower and more congested. The 5 GHz band is faster but has a shorter range — most modern routers broadcast both simultaneously (dual-band).
When your device sends a request — say, loading a webpage — it transmits a radio signal back to the router. The router forwards that request through the cable to the internet, fetches the data, and sends it back wirelessly in milliseconds.
WiFi standards (802.11a/b/g/n/ac/ax) define the speed and range of each generation. WiFi 6 (802.11ax) is the current mainstream standard, handling more simultaneous devices with less interference than older versions.