What is China Telecom mifi and how to use it?

Mifi is a portable broadband wireless device, the size of which is equivalent to a mobile phone. It integrates the functions of modem, router and access point. The built-in modem can access wireless signals, and the internal router can enjoy this connection between multiple users and wireless devices. It is an artifact of 3G and 4G Internet access at present. It is very cost-effective to buy mifi at the most in Sichuan Telecom Network Hall, which saves 69 yuan.