From the Color sub-category of the Formatting panel, you can edit the color for the data points in the chart. If there is no hierarchy in the Color drop zone, and the chart does not contain a legend, the color selection will be applied to all members in the chart.
However, if there is a legend based on a hierarchy, you can change the color for selected members as required; this is known as series editing.
If there is a legend based on a measure, the color can only be changed from the Legend view.
The Color view features two tabs: Fill and Line. To change the color, open the Fill tab.
The options in the fill tab allow you to change the fill type and fill color.
Solid: choose a single solid color.
Pattern: select a pattern and color.
Gradient: select a gradient; choose both the base color, and the end color, to define the range of the gradient