2

What is the proper form?

send an e-mail

send a mail

send mail

3

First of all, it's not often that you'll find someone referring to email as "e-mail". Mostly there is no hyphen. Just a note!

To answer your question, definitely "send an email". As in:

"I'm going to send an email over to Katelyn about that."

However, while this isn't wrong, it's actually most often shortened even more, to just "email" like this:

"I'm going to email Katelyn about that."

Not the answer you're looking for? Browse other questions tagged or ask your own question.