The e-card is sent by email to the recipient you choose during the purchase. The email contains a voucher code which can be entered during the checkout process to reduce the balance of the total. If there is balance on the card unused then this can be spent on the next purchase by re-entering the code. If the purchase exceeds the gift vouchers amount they will be prompted automatically to pay the difference.
Um’s gift voucher remains active for 12 months after purchase so do please encourage their use!