How can you update emergency contact telephone number in the health app?
How can I update an emergency contact telephone number in the health app?
iPhone 11 Pro Max
Open Health app, select your own self-chosen round icon in the upper right, select Medical ID, select Edit, scroll down.
...or if the telephone number of an existing contact has changed, fix that in Contacts.
Your self-chosen round-icon photo is (also) set in your own card in the Contacts app.