Excel automatically distributes these points along a uniform X axis. To add more data to the Y axis in a line chart, add additional numbers in cells below your existing data.

Charts enable your company to display in compelling graphical format the contents of its Excel worksheets. Whether you've created a chart without a legend or deleted a legend from an existing ...

You can add a column in Excel by right-clicking or using the “Insert” option. These features are helpful for adding new data to a spreadsheet.