1. htaccess

The htaccess file is used by apache to apply custom setting to web directry. These settings will only apply to that web folder or website

Apache allows this by setting the command below;

                <Directory /full/path/to/sitefolder/>
                    AllowOverride All
                </Directory>

The permissions for the .htaccess file in the folder mentioned above need to be set to 640 or less.(Read write for owner and at most read for group)