The Email Case is an out-of-the-box Case Type that represents a customer interaction via email. Agents can respond to Email Cases and create new Cases from inside this page. 

Standard email case detail page

Header title

This is the topmost section of the Email case detail page.

Case TypeThe Case Type. The default value is EMAIL
Case IDThe auto-generated unique ID name of the Email Case.

Header toolbar

Right under the header title is the header toolbar that contains the major actions to do on the Email case.

By default it contains:

Milestone Routing buttonsButtons to route the case to the next Case's milestone. These buttons will vary by Case Type.

Summary section

This section contains basic information about the Email case.

MilestoneActual milestone state of the case. This varies by the Case Type.
PriorityPriority of the case.
DeadlineIndicates the time remaining before the SLA Deadline date (in green) or the time passed after the SLA Deadline date (in red)
Mail CategoryEmail categorization for special use. Valid values from the dictionary could be Internal Mail, Emergency Mail, or Microsoft Failed Delivery

Central tabs

The central tabs contain detailed information about the Email case.

Case Emails (99/99)List of all the emails interactions for this case. Ability to reply, forward, attach to an existing case, or detach from the case.
Documents (99)List of all the documents associated with the case. Ability to upload, remove, and view the document.
Related Cases (99)Show any existing link(s) to other cases. Ability to create and link to a new case or link to an existing case.
HistoryProvides an audit log of events that have happened on the Case.

Right tabs

By default, this section shows:

Create New CaseWindow to create a new case of the Type selected. By default Complaint, Inquiry, or Request.
People (99)List of Case Parties associated with the Case. By default Requester.
Notes (99)List of the Notes posted on this Case.