Drag down the "Balances" section to reveal the full card.
You will then see three buttons underneath the image of your Mastercard, "Freeze", "PIN" and "Wallet".
Select "Freeze"
You will then see your Glint Mastercard appear to frost over and will now only see 2 buttons. A Defrost and Cancel button
Please note that if you accidentally cancel your Mastercard using the Cancel button it cannot be reactivated. There is a confirmation window before you can officially cancel your Mastercard to help avoid accidental cancellations.