How to Add Line to Scatter Plot in Excel (3 Practical Examples) - ExcelDemy First of all, right-click on the scatter chart and click on Select Data. Next, in the Select Data Source window, click on Add. Then, in the Edit Series window, set Vertical Line as the Series name. Furthermore, select cell B8 as Series X values and cell C8 as Series Y values. Press OK and this will generate a new data called Vertical Line.