RE: how to send mail from case form without going to email form.
Hi shivamG25,
I also agree that it's no possible to replicate the email entity form inside case form. I think you would like to have an email quick create form just like quick create form of phone call activities. While there's still no available quick create form of email entity. But I think you could refer to the following step by step work-around details if your just want to write the mail and view the case details at the same time from your description.
1. Click 'See the records associate with the view' under Activities Panel
2. When you create a new email record , it would open a new web edge for the mail record.
Then you could write the mail and check the case info at the same time.
For your reference.
Regards
Johnny