Cards are the building blocks on Boards. If each List on your Board represents a specific phase of your project, Cards represent specific elements within a project (a new feature, a software bug, research note, an idea, or paper).
You can attach images and files, make comments, and change colored labels on any card.
You can move or copy cards between Lists to show progress, and automatically move or copy them over to other Lists and Boards using Linkbots. You can also choose to enable a compact view for all Cards on the Board. Compact view shortens the information displayed on a card to allow viewing of more Cards consecutively.