To create a drop-down list in Excel, select the cell or cells where you want the drop-down list to appear, go to the Data tab, click on the "Data Validation" button, go to the "Settings" tab in the Data Validation dialog box, select "List" in the "Allow" drop-down menu, enter the values you want to appear in the drop-down list in the "Source" box (separated by commas), and click "OK".