How to iMessage from an iPhone but not show my number, only an email?

I'm only asking because I don't have my iPhone on me to test it out and find out for myself.

I want to be able to text when I go out too but there's this one person I don't want to have my number, only my email. So is there any way to just use my email on my phone?

Not that I know of. But what I usually do if I don't want them to have my number, get a free texting account and set up a number. Then they won't have your real number