How to make dropdown selection which have a relation?

Hi,
You have to make AJAX calls.
Register an AJAX call handler and add your dynamic dropdowns in your page.
Some help in WordPress Codex.

Look at this demo.

Hope this helps.

Hmm,I am not a coder. I can’t follow it. Is there any free plugin for it?

Hi,
Are you using any forms plugin? Do you want this selection in a form? Or without a form?

Hi, thanks for responding. I am using contact form 7 and ninja forms. I need it in form and stand alone.

Hi,
This can be done with Ninja forms. Check this out.

I know that, I am looking for a free alternative…