Installing an SSL certificate on your domain is an essential step you should take to secure your WordPress site and now with Let’s Encrypt you can get one for free. An SSL certificate encrypts the connection between your site and your visitors’ browser so hackers can’t intercept and steal personal information. Normally, SSL certificates can be cumbersome to install and can get expensive, but this is changing fast.
Source: Adding Free SSL Certificate and HTTPS to WordPress with Let’s Encrypt and Certbot – WPMU DEV
Let’s Encrypt + Certbot provide a straight forward way to add SSL and HTTPS to your website. This article walks you through the steps to get this running on a WordPress site. It’s worth noting that this will likely work on Apache with virtual hosts but it’ll take a bit more work.