Ah, maybe I wasn’t clear enough, caddy doesn’t need a configuration to redirect traffic from port 80 to port 443, it does it automatically: caddyserver.com/docs/automatic-https
If you want to configure an http only site you need to specifically configure it in your Caddyfile.
Here’s an example for a reverse proxy
<pre style="background-color:#ffffff;">
<span style="color:#323232;"># We don't specify the protocol so Caddy assumes HTTPS and redirects any HTTP to secure.
</span><span style="color:#323232;">secure.example.com { reverse_proxy :<port> }
</span><span style="color:#323232;">
</span><span style="color:#323232;"># HTTP is specified so Caddy won't redirect to port 443 nor generate a certificate.
</span><span style="color:#323232;">http://insecure.example.com { reverse_proxy :<port> }
</span>