This tool allows you to automate the installation of Let's Encrypt SSL certificates.
You need certbot as only requirement.
apt install certbot -y
yum install certbot -y or dnf install certbot -y
Installation of certbot-auto is so easy, just clone it with git clone.
After that move into /usr/bin (so you can use as command) mv certbot-auto.sh /usr/bin/certbot-auto.
Then verify that it is executable chmod +x /usr/bin/certbot-auto.sh.
So automate it! Install a crontab as this: 0 3 * * * /usr/bin/certbot-auto.