What it is
Recurring billing creates the same invoice for a customer on a schedule. It suits retainers, rent and subscriptions. It is a separate feature, so turn it on first. If it is off, the page says "Turn on Recurring billing under Features & add-ons". See guide 02.
Create a plan
Open Financials, then Recurring billing.
Choose New plan.
Pick the customer and the product. Enter a name and a quantity.
Enter the unit amount, or leave it blank to use the product price.
Choose the tax.
Set the start date and the next invoice date.
Choose how often, either Weekly, Monthly, Quarterly or Yearly.
Choose Create plan.
Run it
Invoices are generated every day at 06:30 for plans that are due. To make one now, choose Generate invoice on the plan.
To stop for a while choose Pause, and to carry on choose Resume. A plan shows its status as Active, Paused or Cancelled.
Each generated invoice is an issued invoice for the customer, and you find it in your Invoices list.
Change or end a plan
To change a plan, choose Edit on it. You can change the name, how often, the unit amount, the quantity and the next invoice date. The customer and the product stay fixed. Changes apply to future invoices only, and invoices already generated keep the amounts they were issued with.
To end a plan, choose Cancel plan and confirm. No more invoices are generated for it, and invoices already generated are not changed or voided. A cancelled plan cannot be restarted, so create a new plan if you need one.
Edit and Cancel plan show only for people whose role allows them.
Memberships
A separate screen at Commerce, Memberships handles plans, enrolment and member accounts. Its details were not checked.