Wi-Fi at work, and my IPhone?

If I'm connected to my companies Wi-Fi, can they see an email I sent from my IPhone? How about text messages?

Emails maybe, texts no.
And they could only see your email if they really wanted to, probably via MITM.

Email possibly depending on set-up, but, I really really really doubt they are interrupting data packets as that is completely well unnecessary and kind of a waste of time for the IT department. Text messages no because your SMS isn't go through the companies servers.

I wouldn't do personal e-mail at work.
Text mssgs. Done on your phone go through the phone company.
The N.S.A. Reads all your e-mails so there's a caution.