Tethering is a system app that usually comes factory-installed on all Android devices, which allows you to tether using your device. Forcibly uninstalling or disabling this app may interrupt this functionality, so you must manage it carefully.
In short, tethering from an Android device lets you share its Internet connection with nearby devices via Wi-Fi or Bluetooth. It's a feature available on Android almost since the beginning, with version 2.2. This app ensures that all systems continue functioning correctly when using your Android device as a gateway to provide Internet access to other devices.
Like many other system apps, Tethering has no interface. The only way you'll notice if there's a problem with the app is when you enter the tethering section of your settings, you'll receive a persistent error message. If this happens, it's most likely that you've unintentionally deactivated or uninstalled this service. In this case, the best option is to reinstall the app.
Tethering is a handy system app, thanks to which you can turn your Android device into an Internet repeater so other users can connect using your network. You probably won't do it very often, but it's still incredibly useful.
