My iPhone synced with dad's
My dad got me iPhone 7 when I was 11. I set up the phone with my Apple ID but for some reason the phone was always synced with my dad's phone and Apple ID. He could see my call log, messages, photos and notes and I could see his. Even his FaceTime calls ring on my phone. I am 16 now and the problem remains constant. Whenever, I change the Apple ID information in my phone, it changes in his too. Whilst in the MacBook Pro I got this year, I have my Apple ID which is not synced and independent.
iPhone 7, iOS 14