12 Health
The Health app, included in iOS, is where all of your health and activity tracking information is stored. It houses a ton of data. Some of it is obtained from the phone (i.e. steps, etc.) or an Apple Watch (i.e. heart rate, exercise minutes, etc.). Other information is obtained from third-party apps or accessories.
The Health app allows you to customize what items are displayed and tracked, shows you health data from a variety of individual sources, and helps you find new health apps that are compatible with Apple’s HealthKit framework.
Additionally, you can setup your medical ID for emergencies and sign-up to become an organ donor.