A. 1. Go to the app's settings and look for a 'Payment Methods' or 'Account' section. 2. Ensure that you have entered your credit card information correctly and saved it. 3. If the app does not allow saving, consider using a password manager app that can autofill your credit card information when needed.

B. 1. Check if your iPhone has restrictions enabled that prevent saving payment information. Go to Settings > Screen Time > Content & Privacy Restrictions and ensure that 'In-app Purchases' is allowed.