I have forgot my MacBook password, can I open it with ICloud?

Change or reset the password of a macOS user account - http://support.apple.com/HT202860 - "You can change the password that you use to log in to your Mac, or reset the password if you don't remember it."

If you have another admin account set up on your MacBook, you can reset your password from there. If not, you may be able to reset it using your Apple ID or FileVault if enabled.

If you forgot your user or account name on Mac

https://support.apple.com/guide/mac-help/if-you-forgot-your-user-or-account-name-mh35548/mac

If you forget [sic] your login password on Mac, click on this link and select the macOS version you use -->

https://support.apple.com/guide/mac-help/if-you-forget-your-login-password-on-mac-mh11627/mac