Required Field is not working inside Modal form
do you have your inputs inside a form group? are you using the onsubmit trigger to start your workflow?
Yes am using a dropdown select as input field so we have any other changes to be done for select input field?
some screenshots with your layout and your workflow can be useful to useful to understand what you are doing and what’s your problem 
for your information this is just a portion of the info needed to try to help you. things that are missing: details of the layout structure from the side panel, details of the settings of the elements, clear description of what happens and what would be the behaviour that you want to produce.
anyway even without the required attribute you can add a walkthrough condition at the beginning of the workflow to check if you have everything you need to run it.
Steps to reproduce issue- Create a Modal and add a form container inside and add a dropdown select as one of the input field and then try to submit form without selecting the drop down value . Even after this the form is getting submitted with no value selected . I want to make that drop down value as required field
this is much better. I can see you have a workflow on the button as well, are you sure you don’t make the request there as well?
Yes removed the workflow for button
is your button set on type “submit button”?
to use browser validation you need all of this:
- all inputs inside a form container
- a button of type submit inside the form container
- the workflow triggered by a onsubmit event
it works in a modal too
Yes the input select item does it work inside modal?
yes, it works. youneed to be sure you have the 3 conditions I mentioned
as an alternative you can always implement your validation by stopping the workflow based on the input value