Is there a way to send email on a mobile device via Unity?
Application.OpenURL("mailto:yesyoucan@hotmail.com?subject=Email&body=from Unity");
Unity support plugins. Check out the section about iOS and Android. If you can write a plugin that sends an email message, you can use it from inside Unity.
Also, if it's acceptable with you, you can have a server somewhere that creates and sends out emails, and from your Unity application you connect to it using the WWW class, or the WWWForm class (just like there are websites out there where you can fill out a form - and the site will send the information you entered as an email message). The mail won't exactly be sent from your mobile device, but from the server.