Delete Email Messages - DROID Mini / DROID Ultra / DROID Maxx by Motorola
From a home screen, select Apps (located at the bottom).
From the Apps tab, select Email.
From the Inbox, tap the check box located to the left of the corresponding message(s).
Messages are marked for deletion when a check mark is present.
To select all messages, tap the Menu icon(located in the lower-right) then tap Select all.