You can add ISIC to your plastic student card for 15€ / 5 years. ISIC can be added when ordering a student card. You can order from the last page of Frank App or in the browser: https://student.frank.fi/ordercard.
You can buy a digital ISIC card for 5€ / year. You can order from the last page of Frank App or in the browser: https://student.frank.fi/ordercard/digital-isic-card.
You can also buy a digital ISIC card from the link on the back of Frank's digital student card (click on the barcode icon in the bottom left of your picture). Your ISIC number will appear on the back of the digital student card after purchase. Please remember to activate your digital ISIC card in the ISIC App after purchase. Instructions for activating the digital ISIC card can be found here.