Ready notifications can be either sent using text or email. The system prefers sending a text when possible, as outlined in this article about text message notifications.
The notification is only sent if the customer has an email or cell on file, and has the "send notifications" setting on in the customer profile:
A notification is sent when all orders due the same day are racked at the return location. Orders created at a store automatically has its return location set to that store, and as such the notification is sent when the order is racked at the store it was dropped off at.
Similarly, orders created by a delivery driver are automatically marked as 'delivery' being its return location. For route regular and will call customers, no ready notification is sent, however these customers can get a reminder notification the night before their scheduled delivery reminding them to prepare any pickup of more clothes. For on demand customers however, a notification is sent when the order is racked at the plant. The notification includes a link for them to select the day and time they wish to get their order delivered back.