How do I add a customer to a transaction?

You can add a customer before creating a charge by tapping the Customers button on the keypad screen. From there you'll get a form for the customer's details and/or an email for their receipt. Anything you enter is saved to your Stripe account, and a receipt is emailed automatically.

Saving customers lets you charge them again later — their payment info is stored securely at Stripe. You can view your customers anytime in your Stripe Dashboard: dashboard.stripe.com/customers.