Activity History

When a record is displayed to the user, the activity history related to that record appears below it.

The activity history contains:

• Email messages that were sent from the record form.
• Messages received through the Email Channel (generally as a reply to a message that was sent).
• The new old values of any Audited Fields

For Cases, all fields are audited, by default. So for example, any change to the status or priority of a case record is automatically recorded in the case history. For other objects, field auditing must be explicitly enabled.

Learn more: Field Audit Log