The Native Email App
Google’s stock email app that comes with the Android operating system, came preinstalled on all Android devices running on Android 4.4 (KitKat) and below. Vendors who wanted to run their devices on the Android had no choice but to provide the Android native email client as well.
However, starting with Android Lollipop (5.0), Google has nixed out-of-the-box support for its native email app, making it possible for vendors to use Android without being forced to integrate the default apps.