In this paper we have discussed everything about light fidelity (Li-Fi) like working principle, application, advantages, limitation etc. The comparison with Wi-Fi has also been discussed in latter part of paper. The fifth generation mobile communication technology (5G) has already being launched in different countries. The speculative study towards 6G technology has been started by many researchers. After 10 years or more than 10 years, we could assume that 6G might be the reason of the drastic change in the field of data speeds and mobile networks. For the successful deployment of 6g, LIFI technology will be come out as an effective solution for many industries. In the era of 6G technology, we will have more IoT devices, driverless car which enable road safety and new ways of health monitoring, here LIFI act as fundamental in 6G. LEDs bulbs of LIFI will help to serve thousands of applications in enabling smart cities and smart homes. In this paper we have studies how LIFI technology will help and support the 6th generation mobile communication technology.