Lets Encrypt Certbot for Apache on Ubuntu 18.04 LTS

SSH into the server running your HTTP website as a user with sudo privileges.

Add Certbot PPA

You'll need to add the Certbot PPA to your list of repositories. To do so, run the following commands on the command line on the machine:

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

Install Certbot

Run this command on the command line on the machine to install Certbot.

sudo apt-get install certbot python3-certbot-apache

Choose how you'd like to run Certbot

Run this command to get a certificate and have Certbot edit your Apache configuration automatically to serve it, turning on HTTPS access in a single step.

sudo certbot --apache

follow the steps and the certificates and virtual hosts for SSL will be configured.