How can i populate the data when i select from the drop down menu

Hey !! 

I am giving two drop down for State and District, for that if I select state Tamilnadu another the drop down of district should show Chennai, Erode, Coimbatore, etc.

My question is how can i get the districts of Erode, coimbatore etc when i select the state.  

I would suggest you to use the dynamic drop down widget, you will be able to pre-populate drop downs as you need.

Here is the link to the widget: https://widgets.jotform.com/widget/dynamic_dropdowns 

This guide will help you to add the widget to your form: How-to-Add-a-Widget-to-your-Form