How can I leave a comment on a card?
To leave comments on a card, click the card to open the Card Details. Then click Comments button in the “Add properties” section of the popover window on the right.
Now you can enter your comment in the provided field and click on Send.
You can edit or remove your comment any time after it has been sent. Click on the text of your comment, make amendments, and then click on Save changes or click on the Trash button to remove it.