Follow these steps to create a drop-down list in Excel:

1. Open your Excel spreadsheet and click on the cell in which you want to create the drop-down list.
2. Click on the Data tab.
3. From the Data Tools group, click Data Validation.
4. In the Data Validation window, select List from the Allow section.
5. In the Source section, type in your list of items, separated by commas. You can also refer to a range of cells containing data.
6. Tick Ignore blank if you would like Excel to ignore blank cells in the range.
7. Click OK to apply the change to your drop-down list.