Learner Tasks are a module type which allows the course author to define an activity for the learner to complete which is to be marked by a manager in the system.
The author defines, the basic "content" in Training Post which provides the content and instructions for the learner and a marking guide for the tutor.
The learner completes the task, which could involve uploading a document.
The manager then reviews the task submission and decides if the work is complete according to the marking guide. If so they may mark the work complete and leave feedback for the learner. Managers can see which tasks have been submitted and are waiting for review from the Group Report.
See the following articles for further details:
Task workflow - Setting up a Learner Task
Learner Tasks - Learner workflow