I erased iTunes and a want to get it back on my iPhone 5

Read these support articles (section "Restore a built-in app that you deleted"):

Delete built-in Apple apps on your iOS 11 device or Apple Watch - Apple Support

or

Remove built-in Apple apps from the Home screen on your iOS 10 device or Apple Watch - Apple Support

Regards

Giulio

Hi

Go to settings down to reset Restore iPhone back to factory settings.

Set back up over your wifi If it asks if you want to use iCloud backup Say yes to get your apps and data back.

Cheers

Brian 🇬-1F1E7;