Adding action in Dropdown fields in visual composer iview

Hi,

I develop a application in Visual composer 7.0. I want to convert the input field in drop down for selecting the different values. I can change the same by selecting the particular input fields in design screen. But I not able to specify the values, Action for the drop down. Can someone explain how to add the Values/Action for functioning the drop down field in the visual composer iView?

Thanks,

Kundan