Various Effort fields (usually represented in hours) are available across the Agile views:
Actual Effort – Actual Labor Effort is the effort actually expended for the completed portion of the Backlog Item. It equals to the sum of the Activity Log entries.
Estimated Effort – The Estimated Effort field displays the original estimate in hours in order to complete the Backlog Item.
Remaining Effort – The Remaining Effort is the effort left in order to complete the Backlog Item. By default, it equals the Estimated Effort. It is then automatically decreased upon adding Activity Log entries, but it can be overwritten manually
Total Effort
The Estimated Effort and the Remaining Effort fields are only available for Backlog Items whose Type is “Task” when the “Allow Story Points Estimates for Task Backlog Items” option is deactivated (System Settings workspace, Agile Settings folder, Global Options tab).