Drop down lists are created in Excel by using data validation. Data validation lets you specify what information appears in your custom Excel drop down list. Using drop down list lets you pick what information is added to your spreadsheet. Add a drop down list in areas where you want to control the content.
Open Excel 2007 and select column A by clicking "A". Click the "Data" tab. Select "Data Validation." A drop down list appears. Select "Data Validation." The Data Validation dialog box appears.
Click the "Settings" tab. Change the Allow drop down list to "List." Change the Source to "Yes,No,Maybe." Click "OK."
Click a cell in column A. Notice the drop down list in the right section of the cell. Click the drop down list and see the options available.