Dropdown lists should be used when you want users to pick from a list of options.
You can set options in the dropdown list that have an empty value. This can be useful when you want to force users to pick from a list and provide an empty value at the top or it can be used to break up a list, by having empty values in between sections of a list.
When using empty values, it is recommended that you set the required parameter to true, ensuring that users have to pick an item from the list.