Setup a SSL certificate.

The Caddy server, will setup a automatic SSL certificate in most cases, to have a valid SSL certificate you will need a domain name pointing to your server ip with a A or AAA DNS record.

With a DNS record pointing to your server IP you can use theautomatic https feature of the Caddy web server, for this you must update your Caddyfile in /etc/caddy/Caddyfile to list your domain name like this:

example.com, www.example.com {
    ...
}