WikiEditor provides enhancements to the MediaWiki edit page

For installation, once the code is copied into your extensions directory, you can load it for your wiki by adding to LocalSettings.php the line:

wfLoadExtension( 'WikiEditor' );

By default, when installed this extension will be available to all users, and logged-in users can disable it from their preferences. If you wish all users to have it, and be unable to disable it, add it to $wgHiddenPrefs in your LocalSettings.php:

$wgHiddenPrefs[] = 'usebetatoolbar';

More can be found on the extension's page: https://www.mediawiki.org/wiki/Extension:WikiEditor