Can I share my iMac's internet to iPhone or iPad over USB?
This works on macOS 10.12 and iOS 10 without needing a jailbreak or other app.
Later macOS 10.13 enhanced this feature as part of asset caching and Apple Configurator 2 features for multiple iOS devices sharing the Mac network. This is out of the box support, built in to the OS with no extra first party apps or modifications needed.
Before iOS 10 and macOS 10.13, USB tethering only worked in one direction or for one device. Before macOS 10.12 - internet service used to flow out of iOS but not in to iOS from a Mac over USB.