All iPhones come with the Health app, which, along with tracking your steps and other health data, allows you to set up a medical ID. This will display basic personal information, important medical information and emergency contact numbers when accessed from your lock screen. Additionally, your emergency contacts will be automatically contacted and updated on your current location if you make a call using the Emergency SOS feature.
Follow these steps to set it up:
To test that your Medical ID contains all the information you added, lock your phone and then wake it back up to reveal the Touch ID/passcode lock screen. Tap “Emergency” in the corner to bring up the SOS keypad ― you’ll see the “Medical ID” link in the bottom left. Press this to bring up your ICE info as well as emergency numbers that can be tapped and dialed directly from that screen.