How Are Overdue Events Created?

Overdue events are created as follows:

The Overdue Monitor invokes Overdue Monitor Rules to periodically check your accounts (refer to Overdue Rules Are Embodied In Algorithms for how this works). An Overdue Monitor Rule creates an overdue process when an account violates your overdue rules. The overdue process has one or more overdue event(s). The number and type of events is controlled by the overdue process template specified on the Overdue Monitor Rule.
Users can create an overdue process manually on Overdue Process - Main. To do this, they specify an overdue process template. The number and type of overdue events is defaulted from the template.
An overdue event may be manually added to an existing overdue process by a user on Overdue Process - Events.

Note:

Bottom line. Most overdue events are created by the system when it creates an overdue process for delinquent debt. If you need to create an ad hoc overdue event, you can either create an overdue process whose template contains the desired event OR link the desired event to an existing process.