I have forgotten password for macbook air. How do I reset it?

If you mean your Mac login password then that can be reset with your Apple ID Password by following this link:

https://support.apple.com/guide/mac-help/reset-your-mac-login-password-mh35902/mac

If you forgot your Apple ID Password, then along with the support article that was viewed on top, there is this one:

If you forget your Apple ID or password - Apple Support

ps2080 Said:

"I have forgotten password for macbook air. How do I reset it?"

-------

Troubleshooting a Forgotten Mac Password:

Reset the Password Using the Login Screen:

You'd go through your Apple ID to perform this. Find out more here: If you Forgot your Mac Login Password - Apple Support. Make sure that caps lock is not enabled when typing it. No Success? Go here: If you can't Reset your Mac Login Password - Apple Support