Tasks are great for reminding you of upcoming actions you might need to take. When you mark a task complete it is added to the users activity feed.
For instances where you don't need the future reminder, you can add completed activities directly to the profile activity feed. The activity feed is the same place you'll find system events like email opens and application portal logins.
To Start, simply click the large "+" that you'll see on the activity feed screen.
Then follow the prompts in the dialog box and click create.
You'll note that custom activities are not immediately displayed on the feed. Rest assured, they will populate soon.
Once processed, your completed custom activities and tasks will appear in the activity feed along side other activities already recorded by Element451. You can filter to just tasks and custom user activities by selecting the "Custom" option on the Activity Feed navigation.