php.ini

php.ini is the name of the main configuration file of PHP. It acts as the default configuration.

php.ini contains directives. For example, memory_limit or default_socket_timeout.

They may be later redefined using other mechanisms, such as command line options -d, .htaccess or in-code function call ini_set(), although it may vary depending on the directive.

Documentation

Related : Directives, .htaccess, ini_set(), Disable Classes, expose_php, open_basedir, phpinfo(), Configuration