The main configuration file is usually called httpd.conf .
Some sites also have srm.conf and access.conf files for historical reasons .
In addition, other configuration files may be added using the Include directive. Any directive may be placed in any of these configuration files. Changes to the main configuration files are only recognized by Apache when it is started or restarted. One possible use for this would be to add VirtualHosts by creating small configuration files for each host, and placing them in such a configuration directory. Thus, you can add or remove VirtualHosts without editing any files at all, simply adding or deleting them.