On iPhone or iPad: go to Settings
Tap your name
Tap Subscriptions
Tap AppleCare+ or AppleCare plan
Tap Cancel Subscription or Cancel Plan
Confirm the cancellation
On Mac: open App Store
Click your name or profile
Click Account Settings
Find Subscriptions
Click Manage
Select AppleCare+ or AppleCare plan
Click Cancel Subscription or Cancel Plan
Confirm the cancellation
On the web: go to reportaproblem.apple.com
Sign in with your Apple ID
Find the AppleCare plan
Select Cancel Subscription or request cancellation if available
If you cannot cancel in settings or subscriptions, contact Apple Support
Have your Apple ID and device serial number ready