@SrinivasNallavelli

The Compose Email screen can't be customized the screen/view in Constellation. 

@SrinivasNallavelli To find the view name of the Compose Email screen in a CS Constellation application, first open any case or interaction where the Compose Email option is used. Click the “Design” or “Pencil” icon to enable Design Mode. Then click on the Compose Email button to open the screen. Hover your mouse over the email area, and the view name will appear on the right side panel. It will look something like “pyComposeEmailView” or “CSComposeEmailMain”. You can search for this view name in App Studio or Dev Studio to open and check the design. If the view is final or locked, check if there's an extension view or editable copy. Always try to extend or save-as instead of directly changing OOTB rules. This helps you safely customize the email screen in your application.