You can add or delete the WordPress css editor that appears under “Appearance” in the dashboard by modifying the config.php file in the original WordPress folders/files that you installed on your site. The editor allows you to access directly the style.css file on your website. Some developers prefer to hide the editor for security reasons, but doing so limits your access to some other useful files and templates.
Typically, the config.php file is the only file in the original WordPress download that you will edit outside of the wp-content/themes folder. You should not touch the other folders and files that WordPress provides you in the initial download. Those folders and files are core WordPress creations that must be left alone in order for WordPress to function properly.
1. Access your site through your ftp client (in my case Filezilla), and download the config.php file from your WordPress installation to an easy-to-find location on your computer.
2. Open the downloaded config.php file in a text editor such as Notepad++, Brackets, Sublime Text, etc.
3. In this downloaded config.php file, look for the following comment and code:
//Disable File Edits define('DISALLOW_FILE_EDIT', true);
The value of “true” makes the editor in the Appearance menu unavailable. Changing the value to “false” will make it available.
4. Change the value in the code to “false” as follows:
//Disable File Edits define('DISALLOW_FILE_EDIT', false);
5. Upload the edited config.php file to your site and overwrite the config.php file that is there.
6. Visit your website, refresh the page, go to the dashboard, click on “Appearance,” and you should find the editor available at the bottom of the drop-down list of items available.
Caution: It’s not a particularly good idea to edit directly in the editor that appears at the bottom of the Appearance menu, but its presence does make available a number of options to the right of the screen that will make working in WordPress easier. Once you create custom.php (myFunctions.php) and custom.css files, their links will be available in this area, and a number of other files and templates will be displayed there as well.