How to Change Mac Password?

Change or Reset the Password of a MacOS User Account in ...

Choose System Preferences from the Apple menu, then click Users & Groups.
Select your user name from the list of users.
Click the Change Password button, then follow the onscreen instructions.

What Happens if you Forget your Mac Password?

Restart your Mac.
While it is restarting, press and hold the Command + R keys until you see the Apple logo .
Go to the Apple Menu at the top and click Utilities.
Then click Terminal.
Type “resetpassword” in the terminal window.
Then hit Enter.
Type your password and a hint.
Finally, click Restart.