The card description uses the standard Markdown language for text.
Markdown let's you focus on content, not style, while allowing you to structure your text, using :
- Titles, sections, subsections
- Bullets and numbered lists
- Embedding links and images
- etc.
This will work out of the box in card preview, .pdf exports, and cards presented on a klaro website if you have one :

When you open a card, there is an small Open help button below the editor that will show all posibilities :

You can close the help with the cross icon at the top right :
