HTML formatted text will be code as far as Sparkle is concerned, therefore, it would be entered into an embed box on your page. However, there is no real need to create HTML text and add it to the page because that is what Sparkle does. Simply create your text using the various tools and formatting options available to you and the underlying HTML will be created by Sparkle.
@pingo, Sparkle is a code free platform. All the functionality needed to create a website is under the “+” icon on the top bar of the Sparkle app.
Just click on the “Text Box” and it will appear on the canvas, double click into it and you can start placing your text. You can change the text styles (or fonts) by going to the right hand panel once you have clicked on the Text Box.