cPanel & WHM offers Let's Encrypt AutoSSL Plugin. To secure your domains, first install the Let's Encrypt Plugin. Login to your WHM server as a root via SSH, or use "terminal" in the WHM interface. To use the terminal, In the WHM search bar, type terminal and click on the "terminal" option under the server configuration. Lastly, Run the following command in the terminal. /scripts/install_lets_encrypt_autossl_provider Once the installation is done, In the WHM search bar, type Auto SSL and click on the "Manage AutoSSL" option under the SSL/TLS. Finally, Choose the AutoSSL provider to Let's Encrypt, agree on terms of service and click on the "Run AutoSSL for All User" option to install Let's Encrypt SSL for all your domains. To learn more about Let's Encrypt Plugin, Visit the link below. https://blog.cpanel.com/how-to-configure-and-manage-lets-encrypt-in-cpanel/