Https has become a standard for websites and there's no excuse not to have it enabled on the website, especially that it's now possible for free.
Making your website more secure with a free Let's Encrypt certificate is very easy with Certbot.
The prerequisites are to have SSH access to your server that is already online and serving the site over http. In the example I'm setting up the certificates with Apache.
You would need to add the repository for Certbot first:
sudo apt-get update sudo apt-get install software-properties-common sudo add-apt-repository universe sudo add-apt-repository ppa:certbot/certbot sudo apt-get update
After Certbot and the Apache plugin are installed you need to install the certificate with the server:
sudo apt-get install certbot python3-certbot-apache sudo certbot --apache
During the installation you will need to answer some configuration questions like which domains that you would like to include, but they are pretty self-explanatory.
And that's it! Your server is ready to serve the site over https.