...
Reminder - This task will display a note or reminder on the card. There is only one option on this task which is to move the card from active to completed
Confirmation - The confirmation task will require the user to either accept or reject the task in order to complete it
Timer - The timer task allows the user to track time on a card. You can start and stop the timer.
Action - There are currently 2 actions that you can create with the actions task: you can either upload a document or open a URL when the user completes the task.
Prompt - The prompt task allows the user to add a value to a field that is defined in the task screen.
...
The sections below will provide some more information on how to create and configure tasks.