To enable secure connection through SSL on your account you need to create a CSR certificate via WHM panel and then purchase an SSL certificate for the corresponding CSR by contacting a valid SSL provider.
You need a dedicated IP address for the domain, to install the certificate on it. You can read how toChange IP address of a domain in this KB itself.
Please note that the change of IP address will cause a downtime of 4-6 hours.
You can generate Certificate Signing Request (CSR) via WHM >> SSL/TLS >> Generate a SSL Certificate and Signing Request
To generate an SSL certificate:
1. Click on the Generate an SSL certificate and Signing Request link in the SSL/TLS menu.
2. Enter the email address to send the certificate to in the Email Address the Cert will be sent to field.
3. Enter the domain that the domain is being created for in the Host to make cert for field.
4. Enter the administration details of the certificate in the Country, State, City, Company Name, Company Division, and Email fields.
5. Enter the password for the certificate in the Password field.
6. Click Create
This will create CSR and private KEY. After generating the CSR, you can contact any valid SSL provider (eg: Godaddy, digicerts etc) to get SSL cert.
Once you receive the certificate from the signing authority, add it to your website via WHM >> SSL/TLS >> Install a SSL Certificate and Setup the Domain
Copy the certificate (from the .crt file) and paste it in the space provided. Once you pate the certificate, click Fetch, if the details including the private key are not automatically fetched.
Now copy the CA bundle (from the .ca file) provided by the signing authority and paste it in the box at the bottom.
Now check whether the certificate has been installed correctly, from here or here.
You can also generate/install the certificate via the cPanel of the domain as explained here or here.