Change the task state. To do this, select the Message Type that will change the task from its current state into the one you need. Task states and transitions between them depend on the task workflow, which is in turn determined by the category of the task.
Arranging interaction between users. The Handler task field defines the user whose response is necessary to continue processing the task. If you need another user to work on a task (for example, you have code that needs to be tested or you need to ask another developer a question), specify the appropriate user for that task in the Handler field.
Monitoring the progress of a task. In the process of working on a task, you can add messages describing the current state of affairs and specify the time spent on the task.