Edge computing is the technology which came into existence as we encountered some major issues in cloud computing. As cloud computing gives major support for the industrial welfare like infrastructure, platform and software and leads to a new technology like edge computing. In this chapter we will discuss the basic about cloud and edge computing like how to overcome the issues faced by cloud computing with the similarities between cloud computing and edge computing also the variance between cloud computing and edge computing. Later followed by that we will discuss about the merits of edge computing on the basis of cloud computing along with the building blocks of edge computing. Further we will discuss about the key technologies and functionalities of edge computing in which we will discuss the technologies which are helpful to perform the working of the key technologies which are used to make edge computing to perform better in different levels like Reducing computation, Flexibility management, Reducing traffic, Storage acceleration, Network controller, etc. Also, we are discussing with the challenges of edge computing in terms of providing privacy and security to the users can be divided into four different steps. Final we are concluding the chapter with the applications of edge computing as an emerging technology will depend on its capacity to find a solution to the setbacks which are already available system