If-So uses a TinyMCE editor with both visual and text (HTML) modes so that you can basically set up any content.
If you are using a page builder and are looking for a more convenient way to design your content, the styling options that are available for you are:
Gutenberg Users – You can assign conditions directly to a block (or group of blocks) instead of creating dynamic triggers. See how.
Elementor Users – Save any widget or section as a template and apply it inside an If-So trigger using a shortcode. See how.
Other page builders – Design your dynamic content in a new page and use the shortcode inside your If-So trigger to display the page content as your dynamic version. See how.