Step 1. First, go to the card you want to delete and click on the 3 dots icon (ellipsis)
Step 2. Now click on the “Delete card” option
Final Step. After selecting the "Delete card" option, you’re going to see a message that says: “Are you sure you want to delete?”
Now click on the button “Yes, delete it!” to delete your card.
Note: If you’re the board's creator, you can easily delete any card from your board. People who access your board can only delete the cards they created.
If you want to allow other people to delete any card on your board, you’ll have to give them permission. In order to do that, go to the settings of your board by clicking on the clockwork icon. After that, select the option “Allow anyone to edit”. Now other people also can delete any cards on your board.