I can't seem to search the iTunes Store on iPhone 14

The iTunes Store should be automatically signed in when you setup the iPhone.

You can verify this in Settings ➜ Apple ID ➜ Media & Purchases.

If the iTunes Store does not load anything, make sure the iPhone is connected to the internet correctly, either through Wi-Fi or cellular data.

If this is a new iPhone, make sure you transferred your cell service form the old one.

After I updtd to iOS 16.6 I had probs getting into ITunes & App Store but sounds like you can launch them but not sign in?

In my case, after the iOS update somehow my cellular access was turned off for both so I couldn’t connect to them unless I was wifi connected.