Invoice maker can send automatic reminders for overdue invoices.
You can set up a reminder via an invoice or under Settings - Client communication - Payment reminders
Find an unpaid invoice and click on it
Invoice details appear
Swipe on the action sheet below to display the full menu
Select Send reminder from the list
You may be prompted to enter an email address
Reminders are pre-defined and already contain the information about invoice number and due payment.
Pre-set when to send a reminder - on a due date, 3 days after a due date, 7 days after a due date
You can edit the reminder text under Manage texts
You can enable or disable automatic reminders anytime.