What is the Marks card used for?

The Marks card is the control panel that determines how the data points in a view are visually rendered, sitting right next to the Rows and Columns shelves.

• Mark type dropdown chooses the base shape: Automatic, Bar, Line, Area, Circle, Shape, Square, Text, Map, Pie, Gantt Bar, Density, or Polygon.
• Color: drag a field here to encode categories or values as different colors.
• Size: drag a measure here to encode magnitude as mark size.
• Label: controls text shown directly on the marks.
• Detail: adds a field to the level of detail of the view without adding it to color, size, or label — useful for keeping marks separate (e.g. one line per customer) without any visible encoding change.
• Tooltip: customizes what appears when hovering over a mark.

Because most of these properties accept any field you drag onto them, the Marks card is what turns a plain bar chart into a rich, multi-dimensional visualization — encoding several variables (position, color, size, label) into a single view at once.