Why will my phone not allow me to download apps from the App Store

There could several reasons.

You may not have a valid payment method tied to your account?

Your account could be locked if you owe Apple money?

You may be trying to use an App Store in a country different from the country your payment is tied to?

Without knowing what error message you're getting all we can possibly do is guess.

See this link for possible solutions --> If you can’t download or update apps on your iPhone or iPad - Apple Support

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