The AppStore can not be deleted from your device, but it can be restricted. If you have restrictions for the iTunes Store set up in Settings/General/Restrictions, the app can not be located on the device. Only if you disable the restrictions, the app will be shown again on one of your screens.
This article has a list of all default apps that can be deleted and reinstalled in iOS 10:
Remove built-in Apple apps from the Home screen on your iOS device with iOS 10 - Apple Support
If you can't find the iTunes Store to download, setting the phone back to factory settings will put it back again: