Renewal Reminder
Send this ahead of an annual renewal so the charge is not a surprise. It states the renewal date, then lists the plan, date, amount and card, with a Manage subscription button for anyone who wants to change something. Pull the real values from the account, and send it early enough for customers to act before the charge.
Loops
Time it from the renewal date
Store the renewal date, plan, amount and card ending as contact properties, or start the workflow from an event that carries them. With the Stripe integration, the invoice.upcoming event can trigger it. Workflow emails skip unsubscribed contacts, so if every customer must get the notice, send it as transactional email instead, and check whether the places you sell in require notice before an automatic renewal.