This is a very simple WordPress plugin which disables the Visual Editor aka the Rich Text Editor aka TinyMCE for all users across the site.
If you also delete the “wp-includes/js/tinymce/” directory from the server, the visual editor option will disappear from all user’s profiles and it will be impossible for the visual editor to load. This step completes the removal of the visual editor.
Please note: You will need to remove this directory after every upgrade. Every time you upgrade WordPress this directory will be automatically reinstalled.