How do I change my email account password?

In your authorized Plesk Control Panel, open Mail, select your email address, enter and confirm a new strong password, then save with OK or Apply. Available controls depend on your account permissions.

If your Webmail installation exposes a password-change option, you may use that option in its settings; it is not available in every webmail app. Otherwise use Plesk or ask support for the account-recovery route. Update the saved password on your own mail clients afterward. Never send your current or new password in chat.