how do you recover password on Mac air

Try this procedure https://support.apple.com/en-us/HT202860

If you're talking about Activation Lock, see:

Activation Lock for Mac - Apple Support

How to remove Activation Lock - Apple Support

To add to this, if the other articles don’t fix it:

If you can't reset your Mac login password:

https://support.apple.com/en-us/HT212190

Other than that, can you provide more information? Such as what you see on the screen when logging in, attempting to login, and if any error messages or symbols appear?

Do you see any of the symbols in this article at startup?:

If your Mac doesn't start up all the way:

https://support.apple.com/en-us/HT204156

Thanks.

If you Forgot your Mac Login Password - Apple Support