On My Profile, under My Cards, click Add new Card, enter the card number, expiration date and CVC in the secure Stripe fields, complete the CAPTCHA if shown, and click Save. The card is verified and stored with Stripe (not on Sprwt's own servers) and appears as a card tile you can select later at checkout. If the business has Config "Stripe: Enable 3DS" turned on, you may be asked to complete an extra verification step (like a bank prompt) before the card is fully added.