Activation Lock for iPhone and iPad - Apple Support
https://support.apple.com/en-us/108794
What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support
https://support.apple.com/en-us/109511
Récupérer le compte Apple - Apple (FR)
https://iforgot.apple.com/
If you forgot your iPhone passcode or your iPhone is disabled
https://support.apple.com/en-us/118430?iphone-authentication-type=iphone-with-face-id