Screen time
My I phone was set up with a screen time passcode set up by a parent. That passcode has now been forgotten and no one can seem to get rid of the screen restrictions
iPhone SE
If you forget your 4 digit Screen Time Passcode
4 Digit Passcode is for Screen Time Restrictions
4/6 Digit Passcode is for iPhone lock screen
If you can't remember a restrictions passcode that you set on a previous version of iOS, or you forgot your Screen Time passcode, you need to erase your device, then set it up as a new device to remove the passcode.
Restoring your device from a backup won't remove your passcode.
https://support.apple.com/en-in/HT204396
Use Screen Time on your iPhone, iPad, or iPod touch - Apple Support