Let’s assume that you want to configure an email configuration for an “Android device.” Not Knox, not Android For Work (AFW), just basic “Android.” Look at the picture above. That is what you will see in Intune when trying to create an email configuration for a (regular) Android enrolled device. Notice something? Yes, email is not an option! You cannot push an MDM email payload to an Android device by default. This is actually because when mobile device management was developed for Android, it was a very lightweight solution. Policies such as email were not possible back then. Google has since enabled email configurations for its latest Android for Work (AFW) platform, but when it comes to the base Android configurations, email is not possible.
What about an app configuration policy? Nope, you can’t do that either! As you can see above, when you try to create an app configuration policy for enrolled devices, you only have two options: iOS or Android for Work. Regular Android is not supported.
In summary: If you want users to be able to use email on their Android device you must be very careful about whether to have them enroll as an Android or Android for Work device. If they enroll as regular Android devices, they will have to configure their email application manually. Using AFW enrollments is the only way to auto-configure an Android device for on-premise Exchange email (or Knox).
Side note: if you are willing to bypass enrollment altogether, you may be able to use MAM policies to auto-configure Outlook.
This post updated for clarity on 2020-07-26.