A patient gets home, opens the invoice from today's visit, and would rather settle it now than remember on Thursday. The balance is on their screen and the card is in their hand, so Pay now lets them finish it themselves without a call, a payment link or a reply to your email.
Where Pay now appears
Pay now is in the Billing section of the patient's own appointments page in the portal. It shows beside every invoice that still has a balance, except a voided one. Drafts never reach the patient, only invoices you have issued. It needs Square connected and invoicing turned on. A practice with nothing connected never offers a card payment: if a patient does open the form, it says payment processing isn't connected.
Paying, and what the patient can choose
Pay now always charges the full amount due. The patient doesn't type an amount, so there is no partial payment and no way to underpay by a slip of the finger. If they hold account credit, a Use credit button beside it can cover some or all of the balance first.
The card form is Square's own. The number is typed into Square's card fields and Goji only receives the single-use token Square returns, as with charging a card yourself. A patient who has saved cards can pick one, labelled with brand, last four digits and expiry, or choose Use a new card. Saved cards that are no longer available don't appear in the list. The payment form itself has no save-this-card checkbox, so saving a card is done separately in the portal; see patients manage their cards.
What happens next
When Square accepts the charge the page refreshes: the invoice shows Paid, and the payment appears under Payments with a numbered receipt the patient can download. If the card is declined, the reason shows in place and nothing is recorded; the patient can try another card. Each attempt carries its own id, so a double-click or a dropped connection doesn't charge twice.
On your side it is an ordinary Square payment on the invoice, with a receipt number and the invoice status updated, and the same refunds and disputes apply later. The default Payment receipt notification is scheduled as it is for any card payment.