Apple Mail password
How do I change my Apple Mail password?
iMac Line (2012 and Later)
Question marked as
Delete the email account in Mail then add it again. Or, log into your email provider's webmail page and use their change password utility. Then open Mail and change the password for that account when you are presented with the incorrect password notification to the new one you created at the webmail site.
How to change an e-mail account password … - Apple Community