To set the drop-down box in Excel, you can follow the steps below::
1.Select Cell: Select the cell or range of cells you want to add a drop-down box.
2.Go to the "Data" tab: In the excel menu bar, tap the "Data" tab.
3.Click Data validation: In the Data tools group, click Data validation.
4.Select Drop-down list: In the menu that pops up, select Drop-down list.
5.Set drop-down box: In the settings box, select the data you want to be the drop-down box option, either as a single cell range or as a manually entered value.
6.Click "OK": Click the "OK" button to complete the setup.
7.Set up a prompt message (optional): In the Prompt tab of the Data Validation dialog box, you can add a prompt message so that users know what to select in the drop-down box.
8.Set Error Warnings (Optional): In the Error Warnings tab of the same dialog box, you can define the error message that is displayed when the user entered an invalid input.
9.Test drop-down box: After saving the settings, click the drop-down box to test if you can select the predetermined option.
With these steps, you will be able to successfully set up drop-down boxes in Excel to provide a convenient way to enter data. If you have any other questions, feel free to let me know!