In order to install Let’s Encrypt SSL Certificate for your domain, do following steps:
1. Login to cPanel.
2. Select the Lets Encrypt SSL option from Security Section.
3. Click on issue certificate next to domain name.
4. Check all the required domain and click on Issue.
5. SSL Certificate is now installed.
6. Next step is to redirect the website from HTTP to HTTPS automatically, to do so copy the following code at the top in the .htaccess file.