The configuration for Apache Http Server is in /etc/httpd/ for Manjaro and other Arch based Distributions. There is no /etc/apache2/ . If you have a /etc/apache2/ folder check if it is owned by a package.
Of course, if you want you can configure httpd to use /etc/apache2/, but this is something you will need to do on your own.
You can use httpd -M or apachectl -t -D DUMP_MODULES to check which modules are loaded.
Also see the Arch wiki on Apache http server for more information
https://wiki.archlinux.org/title/Apache_HTTP_Server