How do I report a breach in my iPhone 6s?

Start here:--> Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

and/or here:--> If you think your Apple ID has been compromised - Apple Support

Regards

Giulio

Be careful when sharing the device's sensitive and valuable information with friends and family members.

Thumb Rules:

1. Enable  Guided Access before handing over an iPhone to kids
2. Don't share Apple IDs
3. Don't Jail Brea
4. Don't share sensitive information pertaining to your device and payment methods
5. Beware of Phishing

However --> If you think your Apple ID has been compromised - Apple ...