A BizWritingTip reader wrote:? I challenged my boss that we can use the word emails when referring to more than one. But he said that there’s no “s” on the end as in paper mail there’s no “s” on the end. We would never say that we received mails today. Please advise.
BizWritingTip’s response: Technically, your boss is correct. The word email stands for electronic mail. It can be used as a verb (meaning sent by email) or as a noun (meaning a message sent by email). To make the noun plural, some writers prefer to use the term “email messages.”
The Oxford Canadian Dictionary now accepts the commonly-used version “emails.”
Therefore, I am going to say you are both correct.
Note: Email can be spelled with or without the hyphen as long as you are consistent. The Canadian style is to use the hyphen. However, I am seeing more and more organizations dropping it.