Auto renewal of certificate with Caddyfile

Help
1

I found this guide Using Caddy to keep certificates renewed

but how about us that only use caddyfile?

Do I need to add anything beside this:
mydomain.com, www.mydomain.com {
reverse_proxy 185.11.12.13
}
if I wish to have the certificates auto renewed when they get expired?

Thanks in advance

2

Caddy automatically renews certificates for all sites it manages.

The link you found is about using Caddy to only manage certificates but not serve any sites.