A card is a box that groups a small set of related information together. It is like a note card: each one holds a focused piece of information that can be looked at on its own.
For example, a travel page might show one card for each hotel, with its name, a picture, and a short detail. A card can also include a button if there is a clear next action, such as viewing that hotel.
Keep each card focused on one subject. If every card has too much text or several competing actions, the page becomes harder to scan. Use a plain list when the items need little decoration.