I can't find my iTunes on my phone

Do a Spotlight Search for it. Swipe down from the middle of the home screen to bring up the search field, type iTunes into the text field and see if the app appears in the search. If it's in a folder, the name of the folder will appear to the right of the app name and icon. If it appears in the search but you can't find which screen it is on you can go to Settings>General>Reset>Reset Home Screen layout. That will return the home screen to out of the box condition.

Check Settings>General>Restrictions>iTunes Store and make sure it has not been disabled,

Swipe from screens to screen to look for it.

IF none of those suggestions work, you may have deleted the app. Reinstall it if necessary.

1. Go to the App Store.
2. Search for the app. Make sure that you use the exact name of the app. Find the correct name of built-in apps.
3. Tap to restore the app.
4. Wait for the app to restore, then open it from your Home screen.