Short answer: The card is on hold, not charged. Capture it before the hold expires (at least 2 days on a reader, about 7 for a typed card), or the money goes back to your customer.
When you use Authorize only, the payment is held but not yet charged. You'll need to capture it to actually collect the money. If you don't capture it in time, the hold is released back to your customer's card. A card reader or Tap to Pay hold lasts at least 2 days (5 for Visa); a typed card's lasts about 7 days. Need longer? See Extended authorization. It's just like a hotel placing a hold on your card for incidentals.
You can capture a payment two ways: in the app, open the menu, go to Payments, and swipe the uncaptured payment to capture it (or open it and tap Capture), or from your Stripe Dashboard at dashboard.stripe.com/payments.
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