Tag a Case in a Task
When you tag a Case in a Task, you can track how much time has been spent on tasks assigned to that Case. To do this, you must have
Task & Update Timesheets enabled on your project
Cases enabled on your project
Steps
Create a new Task
Select the Contact that the Case is about
Once you have selected the Contact, the Cases box appears as long as that Contact has one or more Cases
Select one or more Cases
Press Save Task. This tags the Case in that Task. Whenever the task is marked as Done, whoever marks it as done will be prompted to log the time spent on that task.