A Wi-Fi network is a wireless communication system that allows devices like smartphones, laptops, and tablets to connect to the internet without using physical cables. It uses radio waves to transmit data between a router and connected devices, enabling users to access online content and services from various locations within the network's range. To set up a Wi-Fi network, a router is typically connected to a modem, which provides internet access. The router broadcasts a signal that devices can detect and connect to, often secured with a password to protect against unauthorized access.