Howdy Robert,
The rich content editor is located in many different areas of Canvas, such as when you are editing a page, assignment or quiz... & many others. You can read more about the RCE here: https://community.canvaslms.com/docs/DOC-10728-67952720342
For example if you are on a Canvas page and click on the edit button, you should then see the RCE.
Hope this helps- let us know.
Sky V.
