In iOS, AMBER alerts are categorized as Government Alerts alongside Emergency Alerts, the latter which amounts to weather warnings or notifications issued by the President.
Provided you’re using an iPhone 4S or later — and your carrier is AT&T, Sprint, T-Mobile or Verizon — you should be able to toggle them on and off.
Step 1: Start by opening your Settings.
Step 2: Tap Notifications, then scroll to the bottom of the page to find the Government Alerts sections.
Step 3: Tap the toggles next to AMBER Alerts and Emergency Alerts to turn them off.