You can purchase certificate from CA certificate authority. You can also go with self signed certificate but it will show browser warning. But this warning is only one time so if you want you can go with it. You can follow below steps to redirect cpanel, WHM, or webmail to encrypted connection.
- Login to WHM.
- Under server configuration, select “Tweak Settings” option.
- From various tabs you have to select “Redirection” tab.
- You will find option “Always redirect to SSL” option, set it On.
- From all three options “SSL certificate name”, “Hostname” and “Origin Domain name”, you have to select “Origin Domain name” option for “SSL redirect destination".
- At last, click on “Save” button.