admin/environment/php extension/iconv
From MoodleDocs
To enable iconv in Windows package installations of Moodle:
- Open the php.ini file found in the moodle/apache/bin folder
- Find the line:
;extension=php_iconv.dll
- Remove the
;
at the beginning of the line - Restart apache for the change to take effect.
Note: The iconv module is now part of PHP as of PHP version 5 so the php_iconv.dll file is not needed anymore. It is no longer included as an extension in the php.ini-recommended file in the PHP Windows binaries package and you do not need to enable the extension in your php.ini. In other words, you do not have to enable the extension=php_iconv.dll line in your php.ini file. See http://www.php.net/manual/en/iconv.installation.php for details.
This page needs to be enhanced by adding corresponding instructions for other kinds of Moodle installations.