Here are a few links that I found regarding wordpress and Let's Encrypt.
- Is there a free WordPress plugin that uses Let's Encrypt for SSL?
- WP Encryption – One Click Free SSL Certificate & SSL / HTTPS Redirect to Force HTTPS, SSL Score – WordPress plugin | WordPress.org
- How to Add Free SSL in WordPress with Let's Encrypt
- https://hostadvice.com/how-to/website-builders/wordpress/how-to-add-free-ssl-in-wordpress-using-lets-encrypt/
- WordPress with Let's Encrypt SSL Certificate on a Load Balancer | Luis Cacho
- Tutorial: Using Let’s Encrypt SSL certificates with your WordPress instance in Amazon Lightsail | Lightsail Documentation