How to download apps on new iCloud account

Add a payment method, you need this even for free apps.

How to change your payment method on your iPhone, iPad, or iPod touch

1. Open the Settings app.
2. Tap your name.
3. Tap Payment & Shipping. You might be asked to sign in with your Apple ID. To add a payment method, tap Add Payment Method. To update a payment method, tap the payment method, then edit your information.

Change, add, or remove Apple ID payment methods - Apple ...