This guide will help you how to change your email account password through Webmail interface. Before proceed further, you need to know your current password, and make sure you able to access domain.com/webmail where domain.com is your website/domain name.
For example: Your domain called yourdomain.com, therefore you should access your webmail as domain.com/webmail
Access Webmail
Go to your webmail by accessing http://domain.com/webmail through your web browser. ie. Chrome, Firefox, Internet Explorer, Edge browser, Opera, etc.
A webmail horde interface will opened for you. After that login to your webmail by input username & password.
Username should contain full email address : email@domain.com
Password should be typed as your current email password.
Click Login.
Go to Preferences
Go to "Gear form Picture" located above > Preferences > Choose Password.
Click for "Password" as below picture.
Change Password
Fill the current password and new password as per below field.
Once finished, click "Change Password".
Now your email account has been changed to a new one.
NOTE : Do not forget to change your email account password within Outlook, Thunderbird, etc.
This article taken from:
https://support.exabytes.com.my/en/support/solutions/articles/14000105668-change-email-password-through-horde-webmail