Blockchain technology is a revolutionary innovation in the Internet world, which is responsible for bringing many changes in numerous sectors and has been adopted by various companies and research communities in recent years. From the cryptocurrency to the current smart contracts, Blockchain presently bringing a strike in various domains like finance, supply chain management, IT governance, the Insurance sector, the Internet of things, and others. With the support of consensus algorithms, secure transactions can be performed over point-to-point connections in a distributed system without requiring a third party. Blockchain is being integrated with many enterprises and their system gets benefit from it. Regardless of recent popularity, the basis of Bitcoin, Blockchain has received little attention. Some challenges are there in security and performance. The goals of this paper are to provide an inspection of Blockchain technology, characteristics, classification, and architecture, to provide insights into the Blockchain application use cases, and to outline the challenges. Further, we summarize the future research directions and further advancements that make the technology a superior option for many communities.