Adding Pop-Up Documentation to a Cell in Excel

1. Select the cell for which you want the pop-up to appear.
2. Display the Data tab of the ribbon
3. In the Data Tools group, click the Data Validation tool. Excel displays the Data Validation dialog box.
4. Make sure the Input Message tab is displayed.
5. Make sure the Show Input Message When Cell is Selected check box is selected.
6. In the Title box, enter a title for the pop-up window.
7. In the Input Message box, enter the text of the documentation you want to appear in the pop-up window.
8. Click OK.