How to: Add a Legend Title to a Legend
To display the legend title, assign a newly created LegendTitle object to the Legend.Title property. Then, specify the title’s TitleBase.Content property.
Note
A complete sample project is available at https://github.com/DevExpress-Examples/how-to-add-a-legend-title-to-a-legend-t377595.
<dxc:Legend>
<dxc:Legend.Title>
<dxc:LegendTitle Content="Area of Countries"/>
</dxc:Legend.Title>
</dxc:Legend>