Step 1.  Login into your cPanel.

Step 2.  You will find the search bar at the top of your cPanel, Search for "Lets Encrypt" and select "Lets Encrypt SSL

Step 3. After clicking on "Lets Encrypt SSL", you have to find "issue a new certificate",  and click on "Issue

Again click on the issue...

Step 4: After clicking "Issue" you will get a success message.