An Automation Process is showing in Process History as not complete, or it does not create the email or document until you complete a Task created in the process.
The reason for this could be that a step in the automation has the task set as a "blocking" task and has Blocking set to "On". This means that until the status of the Task it is set to "Complete", the next step in the process, or the overall completion of the automation, will not happen. This could also be the case if the Process only holds one step.
Change the setting in the Task being created in the Process so it is no longer a blocking task by setting Blocking to "Off".
The Automation Process will then show with no steps outstanding regardless if the task is marked as complete or not.