Hello Swati,

On click of a button(You can make it look like a dropdown), you can call a Local Action. In this flow, you need to define a section where you can provide the options. 

You can implement this by using the table in the section. Then use the Pagelist/ Data page for this.

Your dropdown is ready you can see the changes but you need to still process the selection by using DT/Activity depending upon requirements.

Let me know if this works for you.