MacBook pin
My little cousin pressed some buttons on my MacBook Air and now every time I turn it on it asks me for a pin. I have no idea what the pin could be.
You may have to consider start up in macOS Recovery to see if you can access your user account or the Mac,
&/or perform some kind of reset, or see what options are available; or maybe see if you can login via icloud?
The need to have more than one user account comes to mind where the situation may require access, if or
when other users who have no valid need to play around, gain access without knowledge or valid purpose.
A second user account, or even a 'guest account' may keep another from ruining your user-created projects
and maybe even going online to improper sites for unknown purposes, where you may be held accountable.
• About macOS Recovery - Apple Support
https://support.apple.com/en-us/HT201314
• How to reinstall macOS from macOS Recovery - Apple Support
https://support.apple.com/en-us/HT204904
• Change or reset the password of a macOS user account - Apple ...
https://support.apple.com/en-us/HT202860