Email Quick Compose Custom Field

Hi,
How do I display one of custom fields on Quick Compose Email.
I tried via studio but that doesn’t works.

I want to show the field on Quick Compose, how should I make that work?

Quick Compose (or any other window that shows as a modal dialog on top of the others) is not a view customizable via Studio, you will have to find the PHP file and customize it from code.

Search the files, I think they are called QuickCompose*