Did you know you could send a group email on the iPhone? You do this by creating a group of contacts, then you can send an email to that group. To setup a group, you will need to go to the Contacts app on the Mac, or you can go to Contacts in iCloud.com. Once you create that group, you can then open Mail on the iPhone and send an email to everyone in that group. See how this works in this video on sending an email to a group of people with the Mail app on the iPhone.