Maybe everyone knows this, but I’m pretty tech savvy and I didn’t, so…
Imagine you lose your phone, but it’s locked, how could someone who found it contact you to let you know? Or you’re incapacitated and can’t unlock your phone for someone to dial your emergency contacts, what can they do?
You COULD make an image with your emergency contact and their info on your lock screen, but really no one wants to do that. You COULD stick a business card between your phone and your case, unless you don’t have a case or it flies off or whatever.
Better solution, “favorite” your emergency contacts (in contacts, open the contact, scroll to the bottom and tap “Add to Favorites”). Then lock your phone. From the lock screen swipe left to right to see the “widget” screen. Scroll to the bottom. Tap the “Edit” button. Now you can edit what appears on this screen. Usually it defaults to your calendar, news, weather, and some pretty useless stuff. Remove the useless and add “Favorites”.
Now even when your phone is locked, someone can still call your emergency contacts.
Bonus emergency tip: if you ever use “Hey Siri” to call emergency services, be sure and add “on speakerphone” so you can hear them and they can hear you, even hands-free.