Data Validation: How to create a list (Dropdown)

1. Select the cell/cells where you want to apply the data validation. 
2. Select Data → Data Validation. 
   
   

   

   
   
   
3. Data Validation dialog appears on the Right. Click on Criteria and select List . In the source field,  add the values separated by comma to be populated in the list.
   In the below example, we create a list containing values Pens, Pencils and Clips.
   (Optional)If you want to Ignore the blank cells from the data validation, toggle the switch "Ignore Blank Cells" to ON.
   
   

   

   
   
   
4. (Optional) Enter the message for users
   A message that will be displayed when the user hovers over the cell. You can use this as a message provided by the players.
   

   

   
   
   
   

5. (Optional)Enter Message at input of incorrect values.
   In the lower section of the Dialog, you can choose to display a message when the user enters invalid data. To display an alert, select the "Show Alert" box
   Different Alert types are "Error, Warning and Information". Select the required Alert type, title and the message you want to display.

   

   
   
   

6. Click OK once the values are selected.
7. Note: Any incorrect values will be circled red. Hovering over/selecting the cells will show the input message.
   
   
   

8. Note: If you enter a value outside the list, you would see an error message as below.
   

   

   
   

Multiple choice option

A user can not only select one of the options, but can select multiple options within a cell. You can keep all the selected items in the same cell, separated by commas.

(Repeat steps 1-7 from above)

8. Select on the dropdown list and select one of the options from the dropdown list.

9. Select on the dropdown list and select another option.

See Also: How to use the Data Validation Feature