Apache HTTP server is open-source software and is free of charge. It is efficient in processing static content. It has features like SSL, virtual domains, and CGI. This software also supports PHP, Python, and Perl.
While HTTPD is a software, it also runs in the background to process any server request. HTTPD with reference to Apache executes the process by creating threads or child processes to handle incoming requests.
If you have a Shared/ Cloud or Reseller account, no changes can be done on the Apache configuration (httpd.conf).