How to Geek:

• Drop-down lists in Excel make data entry easier and more efficient by allowing users to select pre-determined values from a list of options.
• To add a drop-down list in Excel, use the Data Validation feature and name the range of cells containing the options. Then, enter the name of the cell range in the Source box of the Data Validation dialog box.
• You can customize the behavior of the drop-down list by checking or unchecking options like “Ignore blank” or adding an input message. To remove the drop-down list, open the Data Validation dialog box and click the “Clear All” button.