If you tap Ask Reason for Calling, your iPhone will ask anyone who calls you from an unsaved number why they are calling you without ringing your iPhone. After the caller answers a few questions, your ...
If identification isn’t enough, you can set the iPhone to block notifications for any number not in your personal network.
In the Settings app, go to Accessibility > Touch > Back Tap and choose one of two options: double tap or triple tap. You should see a list of actions you can run by tapping the back of your iPhone, ...