You want Apache to know that all files with a particular extension should be treated as CGI scripts.
Add the following to your httpd.conf file in a scope covering the areas where it should apply, or in an .htaccess file for the appropriate directory:
AddHandler cgi-script .cgi
The AddHandler directive shown in this solution tells Apache that any files that have a .cgi extension should be treated as CGI scripts, and it should try to execute them rather than treat them as content to be sent.
The directive only affects files with that extension in the same scope as the directive itself. You may replace the common .cgi extension with another, or even with a list of space-separated extensions.
Note the use of the term extension rather than suffix; a file named foo.cgi.en is treated as a CGI script unless a handler with the .en extension overrides it.