Set a Reminder on a Work Item
Reminders are set on each Work Item individually, from the Work Item's own Reminders tab. There is no account-wide reminder setting: a reminder fires for the Work Item you attach it to, on the schedule you give it.
Set the reminder
Open the Work Item you want a reminder for.
Go to its Reminders tab.
Choose Add reminder.
In the reminder form, set Schedule, which is relative to the Work Item's due date, so you can schedule the reminder before it is due.
Set Time of Day. It defaults to 09:00.
Set Channels to choose how the reminder reaches you. The options are In-App and Email, and the default channel is In-App.
Save the reminder.
The reminder now runs on the schedule you set. If you need the work itself routed to a person or group first, see how the Work Queue handles that.