Q: no invite button on iphone calendar app?

Usermom58 Thanks change my default calendar to icloud did the trick.

Hi! I had the same question and I was looking into getting MobileMe until I discovered that iCloud absorbed MobileMe. I have found the most efficient way to get this feature to work is to go to settings. Then, click mail. Then, go to iCloud. Tap the option calandar to merge your email with iCloud. This should give you the feature to do this. Just to let you know, I am using the iOS 6 in 2013 on the iPhone 4 with AT&T.

There is now a new app doing exactly that. ReplyAll app is a new iPhone app which allows to reply to all attendees of a calendar events or forward it to a new invitee as well as replying by SMS to the event organizer. It was created mainly for users who use their iPhone to manage their events. The app was build based on iOS 7 Look and Feel.https://itunes.apple.com/us/app/replyall/id749454893

For anyone having issues make sure to change the default calendar to ICloud.  thats what I did and it worked.  Thanks for the tip