What is TinyMCE?
TinyMCE is a rich text editor that falls under the GNU Lesser General Public License. It extends the content creation experience by offering WYSIWYG editing.
More About TinyMCE
You can undo or redo text, clear formatting, add special characters, edit anchors, and more. This simple editor is similar to using a word processor. TinyMCE also enables you to use keyboard shortcuts to copy, paste, select all, bold, underline, etc.
Although WordPress has a new default editor, you can revert to TinyMCE by downloading the Advanced Editor Tools plugin. The Classic Editor plugin can also enable you to switch between the two different editors.