Q: change password in Mail

Who is your email provider? If you are using iCloud mail, then you need to change it in your iCloud mail account:

Your Apple ID

    1.  Apple ID - Apple Support

    2.  Manage your Apple ID primary, rescue, alternate, and notification email addresses - Apple Support

    3.  About your Apple ID email addresses - Apple Support

IMAP or POP account(s)?

Try going to System Preferences/Internet Accounts and change the password there.

You are welcome.

Sorry but I have the same question and when I go to system preferences/ Internet accounts and I click my email information I don't see anything to change the password.

Is you select the account, there isn't a place to enter a password on the right?

Yes, but if I type the new password it keeps telling there is an error. I am going to call Apple. This is a little ridiculous. Thank you very much for the help.

You are welcome.