Wireless internet and WiFi often get confused as the same thing. Wireless internet is a type of internet service, others include DSL, Cable, FiOS, Dial up, and Satelite, etc. Wireless internet can be provided by a local internet service provider (ISP).
WiFi is a wireless network that can be set up in a home, business, etc, regardless or the type of internet service you have. People with WiFi enabled devices, such as laptops or phones, can connect to that network
and use the internet wirelessly. The networks can be password protected so only those authorized to use them have access. Without a wireless network, computers have to be hardwired for internet access.