Reseting Macbook Air

Hello,

to do a factory restore (including macOS), please follow the instructions matching your cpu:

erase a Mac with Apple silicon

erase an Intel-based Mac

If you don't want to reset to factory-defaults, you can try to change the admin pin:

Reset your Mac login password - Apple Support

What to do before you sell, give away, or trade in your Mac - Apple Support

How to reinstall macOS

After erasing the disk, you can reinstall in Recovery Mode

Intro to macOS Recovery