Change data markers in a line, xy (scatter), or radar chart

In a line, xy (scatter), or radar chart, click the line with the data markers that you want to change.
This displays the Chart Tools, adding the Design, Layout, and Format tabs.
On the Format tab, in the Current Selection group, click the arrow in the Chart Elements box.
Click the series for which you want to change the data markers.
On the Format tab, in the Current Selection group, click Format Selection.
Click Marker Options if it's not selected, and then under Marker Type, make sure that Built-in is selected.
In the Type box, select the marker type that you want to use.
In the Size box, select the size that you want to use for the markers.