When I try to install apps my iPhone says”this Apple ID has not yet been used in the iTunes Store” what do I do?

The resolution to this issue is often making sure you have entered a credit card or other valid method of payment even if you don't plan on needing to use it. The document 'If you can't remove your last payment method or use no payment method with your Apple ID' mentions "if you're using an existing Apple ID with the App Store for the first time, you must provide payment information," in this link: https://support.apple.com/HT203905

If there is an option to select "Review" or "Continue", select that and enter valid payment information if required. If there's problems doing this:

Tap: Settings > [your name at the top] > Media & Purchases > View Account > Review Apple ID.

More things to try in this 2018 post by Urquhart1244 marked Apple Recommended:

https://discussions.apple.com/thread/8434425?answerId=33542414022#33542414022

Payment methods that you can use with your Apple ID - https://support.apple.com/HT202631

I click review. This asks me for the password again. Then takes me back to "this Apple ID has not yet been used in the iTunes Store". Just going around in circles!

Log into your account in the App Store/iTunes and you should be able to change/verify it there.

Apple ID has not yet been used with the iTunes store. Please review your account information