Blockchain is a new distributed ledger system that enables for safe online transactions without need for a trusted third party. As blockchain technology continues to advance at a dizzying pace, the question of smart contracts and how they should evolve has risen to the forefront of academic and business discussions. With this paper, we want to shed light on how smart contracts built on the blockchain really function. To better grasp the whole picture, researchers are taking into account scholarly works that have been vetted for their quality and are presenting a comprehensive overview of the relevant literature. Future work on decentralized apps might benefit from this. The first part provides a high-level introduction of smart contracts, covering topics such as their rationale, structure, and use cases. In addition, a thorough analysis of other smart contract development platforms reveals that the blockchain used in research is the most effective platform for improving QoS. In other words, it is developing low-cost smart contracts for distributed applications. Further, we give simulation work that uses the Blockchain transaction as a data set to educate an AI model that can help forecast whether or not the transaction will be successful. Finally, this paper also emphasizes key difficulties and future research implications in the decentralized uses of Blockchain smart contracts.