The help section refers to those 2 paragraphs about scheduling recurring invoices but doesn't explain HOW!
How do I schedule recurring invoices?
You can set invoices to repeat weekly, monthly, yearly, or at a custom interval. When you start a recurring series of invoices, the customer will immediately receive the first invoice. (You also can schedule the recurring series to start at a future date.) The following invoices in the series will issue around 7:00 AM in your time zone according to frequency that you set.
Can I cancel a recurring invoice series?
You can cancel a single invoice within a recurring series or the entire series of invoices. To cancel an invoice, tap the three-dot icon for the invoice within your list of invoices. You can also cancel the invoice from its details page. When you cancel an invoice within a recurring series, we’ll ask if you want to cancel the single invoice or the entire series.
