Try your Apple ID if the Mac login screen offers a reset option
Restart the Mac and use the built-in password reset prompt if available
Use another admin account on the Mac to reset the password in System Settings or Users & Groups
If FileVault is enabled, use your FileVault recovery key to unlock the disk
If you forgot the password and have no reset options, restart into macOS Recovery
In Recovery, open Terminal and use the password reset tool if available
If the Mac is managed by an organization, contact your IT administrator
If none of the above works, erase the Mac and reinstall macOS
Restore your data from a backup after reinstalling macOS