How to add space when multiple drop down entries is passed into a field?

I have a text field set up to use the form field value for one of my drop downs

{dropDown}

The problem is when there are multiple options selected in the drop down they display like this in the text box:

   onetwothreefour

Can I set it up to have spaces or commas or other formatting between the selected options when passing this to a text box? 

Unfortunately, that is hard coded from the source. It's currently not formatted in "Text" element. What you can use is the multiple choice field. Selecting multiple items will automatically format and adds "," comma.

ex.

Would using multiple choice box works for you? Looking forward for your response. 

Thanks, good to know. I'd prefer to use a drop down in my particular situation but we'll see