I see that it's important to create a great experience with the students through the online platform, to reward students for completing an assignment. I am thinking about a button they click after completing an assignment that adds points to their course score and gives them a congratulation message that we can adjust according to task, s.th similar to the congratulation message on Facebook. These effects raise the dopamine level of the students and help them be more engaged with the task, having a fun and rewarding factor, like in a game.