Why can’t I download any apps from apps store?

See -> If you can’t download or update apps on your iPhone or iPad

If you can’t download or update apps on your iPhone or iPad – Apple Support (UK)

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Add a payment method

You may need to have a valid payment method on file, even if the app you want to download is free.

Add a payment method

Resolve a problem with your payment method

If your payment method has expired, declined or failed, or a message says "There is a Billing Problem with a Previous Purchase"

See also:

Manage App Store purchases, subscriptions, settings, and restrictions on iPhone

Manage App Store purchases, subscriptions, settings, and restrictions on iPhone – Apple Support (UK)

Prevent in-app purchases from the App Store

Prevent in-app purchases from the App Store – Apple Support (UK)