To highlight lines in an existing Excel document, click the "File" tab. Click "Open," browse to the spreadsheet and double-click it. Otherwise, Excel opens a new spreadsheet for you to use.

How to Highlight Intervals in Graphs in Excel. The interval between the gridlines in an Excel chart is typically blank, but you can highlight the intervals using an alternating pattern by changing ...

To change Gridline color in Excel, use Excel Options, apply a custom-colored border to the cells, or apply a custom line color. Full details here.

How to highlight values Excel has a built-in conditional rule that highlights unique values. You don’t have to come up with a special formula—you just run though a few clicks.

By using the Highlight Cells Rules, you can highlight duplicate cells in your Excel worksheet to avoid confusion and mistakes.