How to Change Grid Line Colors on a Chart With Microsoft Excel. Grid lines add horizontal and/or vertical lines to your graph that aid in measuring graph values. By default, these grid lines use ...

In Microsoft Excel, to draw attention to a specific marker in a line chart, drop in a thin line, think of it as a marker.

Line charts use one or more horizontal lines to visually depict data points. The chart distributes categories evenly along the horizontal axis and values evenly along the vertical axis.