How to Erase All Email at Once on an iPad
The iPad is a tablet computer that uses Apple's iOS operating system. The iPad's Mail application manages and stores email messages on your device. The Mail application does not offer a one-touch solution to delete all your email messages from the Mail application. However, you can manually select multiple email messages to delete simultaneously from the iPad's Mail application.
Tap the "Mail" icon on your iPad.
Select the mailbox that contains the email messages you want to delete.
Tap the "Edit" button.
Manually tap the circle located to the left of every email message that you want to delete. As you tap the circle you will see a red circle with a check-mark displayed.
Tap the red "Delete" button located in the lower-left corner to simultaneously delete all selected email messages at the same time.