How can I erase all emails at once on the iPhone as I can on the iMac?
You can tap on "Edit" select each email and then tap on delete.
I know that works but I want to select all and erase all at once instead ofo going through 65 emails one at a time.
You can't from the Mail app itself. If the account is an Exchange or IMAP, you can delete them using a browser (on iPhone or computer) and they will then be deleted from the iPhone Mail account.
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