I'm not sure what screen you're referring to. Perhaps the admin content list? Typically content producers will add content via the "add content" link/button (de

I'm not sure what screen you're referring to. Perhaps the admin content list? Typically content producers will add content via the "add content" link/button (depends on your theme), edits are possible from any screen where the content is displayed. Drupal supports a number of rich text editors, TinyMCE is only one of them.