Add the delete action, archive, move to icons to bottom of screen
At the bottom of the screen it would be better since there is space on the bottom action row to add icons for delete, archive, move to folder so it's easier to do rather than having to reach to the top of the screen to delete emails.
A.J. Bisci commented
Reaching up to switch accounts is not user friendly.
This is how Outlook for Windows 10 Mobile was and it was far superior to the Android version.
Chris Leonard commented
make the button configurable