If you have already created a chart in Excel, you can embed and link it to your PowerPoint presentation. When you embed an Excel chart in PowerPoint, any updates you make to the original Excel chart will automatically update in your presentation, as long as the files remain in the same location. This helps the data stay in sync, so you won't have incorrect or out-of-date information in your chart.
To edit an embedded chart, double-click the chart. An Excel spreadsheet containing the chart's source data will appear. After you have finished editing, be sure to save the chart in Excel.
Once you have embedded a chart, be careful not to delete or move the original Excel file. If the location of either the PowerPoint presentation or the Excel file changes, you may have to embed the chart again in order for it to display correctly.