Tom Giangreco writes:
I’ve created a number of groups in Mail on my Mac, and know I can use the Group name to address an email to everyone in the group. How do I do the same on iOS? Using the Group name in Mail in iOS doesn’t work.
This is a poser, as I can’t replicate it: I can go into Contacts in OS X, create a group, and then use Mail in OS X and Mail in iOS to enter the group’s name and have it replaced by all the associated email addresses. (Make sure every contact in the group has an email address if you don’t want to crash Mail for OS X.)
I asked colleagues, and it looks like some people running Mountain Lion and later have a section in Contacts labeled On My Mac, just like the On My Mac section in Mail for locally stored email. I don’t see this on my computer, and looking at screens people have posted of their 10.9-and-later Contacts, I can’t find other instances of it.
Read more here:: How to create email groups in iOS