Google Play Store without payment method issue

My mother has retired and is using a cash account. Her account no longer can provide payment details to Google Play Store. When she opens the Play Store, to update her apps on the phone, it advises the following, "You haven't set up purchase verification". It gives you the option of biometrics or password to press on. I reckon it had two do with Two Factor Authentication. Does anyone know how my mother can proceed without providing this information, as my mother has no account that allows internet payments any more.