Follow the below steps
1. Login in to Cpanel and search SSL/TLS in Security click on it
SSL has same account with that domain name skip these step
2. A new screen comes with 4 options click on 2nd one (Certificate Signing Requests (CSR))
Generate, view, or delete SSL certificate signing requests.
3. Generate a New Certificate Signing Request (CSR) by entering details
4. Copy the first box code and connect it with your SSL by selecting CSR option.
5. Download the SSL certificates files using apache selection in the dropdown from SSL Panel.
5. Go back to SSL/TLS third option (Certificates (CRT)
Generate, view, upload, or delete SSL certificates.
Fill Generate a New Certificate form
6. Go back to SSL/TLS third option (Certificates (CRT)
Generate, view, upload, or delete SSL certificates.
upload certificates which have .crt extension.
7. After upload, both files go to the last option
Install and Manage SSL for your site (HTTPS)
Manage SSL sites.
8. click on the Browse Certificates button then your uploaded certificates appear.
Click on Install Certificates at the bottom of the form.
Success msg appears to click ok.
You have successfully installed on the domain.
Check your domain using https and its working fine.