Patient portals is a prominent area of research within health informatics and healthcare delivery science investigating secure online platforms designed to provide patients with electronic access to their personal health information and communication tools for interacting with healthcare providers. This research explores their design, implementation, adoption rates across diverse populations, usability, impact on patient engagement and health outcomes, effects on patient-provider relationships, and integration within clinical workflows and the broader digital health ecosystem. Key characteristics examined include functionalities such as access to medical records, lab results, clinical notes, appointment scheduling, prescription management, and secure messaging, analyzed through frameworks of technology adoption, human-computer interaction, and health behavior. Their significance lies in their potential to empower patients, enhance shared decision-making, improve care coordination, facilitate chronic disease management, and contribute to the transformation towards more patient-centered and efficient healthcare systems.