How TinyMCE works
This editor’s tools display a preview of what you’re adding to the page in a visual editor. You can see all changes , text highlights, added images or other files in a text editor as text with html codes.
Thanks to TinyMCE , the visual editor displays them as a preview of the page content. When working on a website, it helps to better imagine what the created post or page will look like after publication.
The new Gutenberg editor from WordPress version 5.0 no longer uses this editor. If you want to continue working with the usual editor, you can install the Classic Editor plugin. Classic editor allows you to create pages using a text and visual editor.