In the event that you are using HTML tags to format your description field (for example <br> or <li>), it is important to note that these will be removed when the feed arrives in Mirakl.
How to format the description anyway?
To format your attributes, you can use the fields available for the product description, for example: "Unique Selling Point 01", "Unique Selling Point 02", "Unique Selling Point 03", etc.