It depends. You can install it with nix/guix and configure it as in any other Linux distro.
Or, if it's a service you want to make the configuration totally reproducible, you can use https://www.gnu.org/software/guix/manual/html_node/Services.... interfaces for those packages that have some written for them.
But there's nothing wrong with regular dotfiles.
I never really tried guix, but that's how nix works ( https://nixos.org/nixos/manual/index.html ). So how does Apache configuration on upstream (meaning, how it's configured on Windows/Linux/FreeBSD) correlate to how it's configured on nixos/guix?