The News app doesn't appear on the home screen when I erased my iPhone 7 Plus and restarted it.

Try these remedies:

• Check Settings > General > Language & Region to be sure your Region is set to "United States"
• Use Spotlight to search for "News". Perhaps you inadvertently placed it in a folder or a different screen.
• If "News" is not on the iPhone anywhere, visit the App Store. Tap "Search" on the bottom right, then type "News". Download the app from there.

As this article explains, the News app is currently only available in Australia, the United Kingdom, and the United States.

Use News on your iPhone, iPad, or iPod touch - Apple Support

Your Apple ID is in the United States.

Are you there as well? If not, that would explain the issue.