Use the Health app on your iPhone or iPod touch

1. Open the Health app and tap the Summary tab. 
2. Tap your profile picture  in the upper-right corner. 
3. Tap Health Details, then tap Edit. 
4. Add your information, like your date of birth and blood type. 
5. Tap Done.  
6. You can also set up your Medical ID or register to be an organ donor from your profile. 

Your Apple Watch uses your personal information to calculate how many calories you burn and more. You can choose to share this information with other apps and it’s kept up to date across all your devices.

After setting up your Health Profile, you can review your Health Checklist initially from the Summary tab. The Health Checklist lets you see and enable available health features. You can also tap your profile picture in the upper-right, then tap Health Checklist to access it.