On cPanel you can set your webmail preference to automatically utilise each time you log into webmail.

There may be times when you want to change or remove the automated selected webmail application and change to a different application.

Please follow this guide for cPanel

1. Log into your cPanel account.
   Follow this guide to log into your cPanel account. Click here
   
2. Access File Manager on the account.
   
3. Head to the filepath /home/username/.cpanel/nvdata
   Note: Your home directory may look different, and replace the username with the username of your account.
   
4. Look for the file that shows the email address with "_default_webmail_app" appended to it. Right-click the file and click delete.
   
5. You can now log back into your webmail and choose your preferred webmail client.