A health information system (HIS) is a system that incorporates data collection, processing, reporting, and use of information to improve health service effectiveness and efficiency through better management at all levels of the health system.

It includes all health data sources, such as data from health facilities and communities, electronic health records for patient care, population-based data, human resources data, financial data, supply chain data, and surveillance data, as well as how this data is used and communicated.

Reference:
https://www.undp-capacitydevelopment-health.org/en/capacities/focus/health-information-systems/#:~:text=Definition%20of%20health%20information%20system,all%20levels%20of%20health%20services.