Depending on your user role and your company settings, a Task Owner field may be visible on each task. This field allows the author of th report to allocate a task to another user (the 'owner') at the time they create or edit a task. The field is automatically populated with a list the names of all users who have the Task Owner role.
If a Task Owner is set on a task, then when the parent report is synced to the portal and subesequently approved, an email will the sent to the owner informing them of the task, and providing a link to open & edit the task.
The Task Owner can also be set, or changed, on the portal.