Navigate to the invoice for which you wish to refund. (You can access the invoice in Stora and select View on Stripe)
Click on the drop-down menu and select Issue a credit note from the drop-down menu.
Then, on the invoice, alter the amount to be refunded if necessary and select the card from the drop-down field titled Select how to credit. When happy with the details, choose Issue credit note to confirm.
Note: Please advise your customer that it can take up to 10 working days for a refunded payment to appear in their bank account.