Settings → Reminders.
Switch on chasing for invoices, estimates or both, set the days, and choose how each step goes out:
Day 3 → Email
Day 10 → Text message
Day 21 → Phone call
A third email is not a third chance — it lands where the first two did. Somebody who has read past two emails will read a text, and somebody who has read past a text answers a phone.
It stops on its own
Three chases and it goes quiet. It also stops the moment the thing it is about changes: paid, voided, accepted, declined, expired. You can mute any single document without switching the whole thing off.
If a channel cannot be used
No mobile number on file, or the carrier registration still pending, sends that reminder by email instead of skipping it. A chase nobody knows was missed is worse than one that arrived another way. The panel records which channel actually carried it.
Phone calls need your say-so
An automated call to a US mobile is regulated: you need the customer's prior express consent, and the penalties for calling without it are per call. A call step is sent as a text until you tick the box saying you have that permission. It is your decision about your own customers, not a setting we can make for you.
The call opens with your business name before any figure, says what it is about, and offers to text the payment link if they press 1. If a machine answers, it hangs up.
WhatsApp cannot be used for chasing
Meta only lets a business write freely to somebody within 24 hours of their last message. A reminder goes to somebody who has not written in weeks, so it would need a message template approved by Meta in advance. Choosing WhatsApp here sends a text instead.