Currently if text fields (headings, rich text, text blocks, text links etc) are empty, they cannot be edited in the Editor.
For some text elements such as buttons and headings, a pencil icon is visible - but on clicking this icon nothing happens, and lots of errors pop up in the browser developer tools console.
This has been flagged as a bug elsewhere on the forums (link), and I have communicated with Support on this, but they've described this as 'expected behaviour'.
It is surely not a technical limitation, since the empty div remains present in the DOM with all of its Webflow data attributes and styles, so the Webflow Editor should be able to recognise which empty DOM elements can be edited and which can't.
The only workaround is to bind these text fields to the CMS, but this falls down on three main areas:
It creates a non-intuitive experience for the client. Some fields are editable from the Editor, others are editable from the CMS.
It's very limited in scope - there are limitations on the number of fields, collections and collection list items, so larger sites will quickly run out of CMS capacity if every text field gets bound to a CMS field.
It's very time consuming to set up and introduces bloat into the HTML markup.