The most likely reason is that the text editor module isn't loading in your browser, can you see the Rich Text formatting options shown below?

Reopen the browser (either Firefox or Chrome are recommended)

Ensure you are logging into your software using https:// secured login. 

Go to the property and edit the listings, if the editor is still not loading reload the page and the editor should load and be available to edit

When adding text to text fields, we don't recommend copy-past but If you are copy-pasting, especially from MSWord or other websites