I created a different Apple ID in iPhone, when I downloaded an app it says this Apple ID hasn’t yet been used in the iTunes Store. Tap review to sign in, then review your account information. I tap review. Then said please enter your Apple ID and pas

Well, absent a specific requirement to split up and/or abandon purchases and the rest, I’d cease using the new Apple ID, reset and reload the iPhone under your existing Apple ID, and use your existing one.

Purchases and subscriptions and such cannot be transferred among Apple IDs.

On your present path, authorize your account, register a credit card or other financial info (or set up a no-purchase Apple ID), and continue setting up the new Apple ID.

Create or use an Apple ID without a payment method - Apple Support

If you can't remove your last payment method or use no payment method with your Apple ID - Apple Support