WiFi uses radio frequencies in the 2.4GHz and 5GHz bands to enable wireless networking. It uses protocols like 802.11b, 802.11a, and 802.11g which define operating frequencies and data transmission rates. These protocols use techniques like spread spectrum and CSMA/CA to allow multiple devices to share the wireless spectrum and avoid interference between connections. Newer standards like 802.11n and WiMax promise higher speeds but come with increased complexity and costs.