Samsung bundles a bunch of stock apps, including an email client, with most of its Galaxy devices. Like many other brands, Samsung has started listing the stock apps for its smartphones on the Play Store. This way, Galaxy devices owners can keep their stock apps updated easily through the Play Store.
The Samsung Email app has all the features that you would expect from an email client, including POP3, IMAP, and ActiveSync support. It supports push notifications, combined inboxes, and threaded messages too. The app can now be updated without a need for a full firmware or operating system upgrade.
As you would already know, the app is compatible only with Galaxy devices.
Update: You can see the app on the Play Store only if your Galaxy device is running Android 7.0 or above, but you can it download the APK file for the Samsung Email app from our database.