Excel

Hi Sue, Thank you for your post, welcome to the forum, in answer to your question, the data source for your chart is either on the same sheet, or if your chart is on a chart sheet will be in another sheet or even workbook. To edit the data on the chart, you must return to the original data, and make your changes there, the chart will immediatly reflect these changes. To quickly get back to the source data, if you are on a separate sheet, click the Chart to select it, then choose the menu command Chart>Source Data, this will open the data sheet and show the Source data dialog box which allows you to make your required changes.
I hope that has helped, best regards Pete