The estimation method for Tasks and Issues is “Time”, where you can log effort in hh:mm (hours and minutes).
Different Estimation methods are only supported for the User Story. While estimating a User Story size, you should also take into account all its underlying Tasks. To estimate effort on Task and Issue, you can use Effort Log feature.
To set effort log, open task or issue in detail view. Open Effort Log tab and log the effort estimate using button. There are 3 parts of the log: Effort Estimate, Effort Remaining, and Effort Logged (Spent).
Using effort log helps you note down actual time and effort spent on a task or issue. Associated User Story shows the sum of this effort log. This sum helps the team in realizing actual effort time and better estimation of User Story size next time.
In Sprint and ToDo boards, effort log feature is also accessible via the widget.
Sprint board configured to follow Scrum, also show the summary of associated items effort under User Story widget. A Kanban board does not show this summary under User Story though.