A drop-down list is a great way to ensure that your users enter data that is consistent with what you are expecting. By providing a list of valid entries, you can prevent errors and improve the overall quality of your data. Excel makes it easy to create a drop-down list, and you can even make a single-use drop-down list that will only be used once and then deleted.

To create a single-use drop-down list in Excel:

1. Open your workbook in Excel.
2. Select the cell or range of cells where you want the drop-down list to appear.
3. On the Data tab, in the Data Tools group, click Data Validation.
4. In the Allow box, click List.

5. In the Source box, type the entries that you want to appear in your drop-down list, separated by commas.

   For example: Red, Green, Blue

6. 
   

7. " In the "Input Message " box , type a message to display when the cell is selected . This message will explain what should be entered in the cell . For example : Please select a color from the list . < div class = "MsoNormal" style = "margin : 0in 0in 10pt ; " >< span style = "font - size : 11pt ; font - family : ' Calibri ', ' sans - serif ' ; color : rgb (34 , 34 , 34) ; ">" If you want this message to appear every time someone selects the cell , select Show input message when cell is selected . < div class = "MsoNormal" style = "margin : 0in 0in 10pt ; " >< span style = "font - size : 11pt ; font - family : ' Calibri ', ' sans - serif ' ; color : rgb (34 , 34 , 34) ; ">" In the Error Alert tab , select Show error alert after invalid data is entered . This will display a message if someone tries to enter an invalid value in the cell . For example : You must enter a value from the list . < li >< p >< span style = "font - size : 11pt ; font - family : ' Calibri ', ' sans - serif ' ; color : rgb (34 , 34 , 34) ; ">" Click OK to save your changes and close the Data Validation dialog box .