Blockchain is a digital ledger where the data entries are recorded in a decentralized fashion that cannot be altered. This is likely to prosper in a variety of industries, including healthcare. According to a survey, 70% of healthcare professionals believe that blockchain has the largest influence on clinical report management, regulating documents, and creating a framework for sharing electronic health records (EHR) in the healthcare industry. Even though blockchain technology is having real potential for improving health information systems, the rise of this technology has also led to innovative proposals and applications. This review mainly focuses on EHR data exchange between the patient and the hospital entities like doctors, record verifiers, insurance companies, pharmaceuticals, etc. The proposed research study has also discussed about the techniques used in these models to counter the problems present in the traditionally used server-client model like a data breach, Unauthorized access, centralized data management, etc., and improvisation of the blockchain-based models. Further, a comparative analysis has been provided on various blockchain-based systems for hosting a secure EHR sharing.