Hey jasnoor4k,
Thanks for using Apple Support Communities. If you've forgotten your Apple ID password, these steps will help reset it: If you forgot your Apple ID password - Apple Support
You mention resetting your MacBook Air, updating it, and not knowing the Mac admin password. To update your Mac, these steps show how: Update macOS on Mac - Apple Support
If you're wanting to reset the Mac user account password, these steps will guide you: If you can't reset your Mac login password - Apple Support
When you say reset your Mac, are you wanting to completely erase the data and restore it to factory settings? If so, these are the steps to follow: Erase your Mac and reset it to factory settings - Apple Support
We hope this helps.
Take care!