When collaborating on a task, you can assign it to colleagues.
To assign a task:
Create the task.
On the Tasks Ribbon, on the TASK tab, in the Manage Task group, select Assign Task.
Enter the person's email address in the To field.
Leave the Keep an updated copy of this task and the Send me a status report when this task is complete check boxes checked to receive updates and a status report when your colleague updates and completes the project.
Click Send to send the task to your colleague.
Your colleague can now add the task to his or her task list.