Unfortunately, there is no automatic response feature for the iPhone, listen up Apple!!, however, there is a quick function with the iphone that I use for my “out of office” text message. I explain how it works in the video below.
In Summary, you are creating a text replacement shortcut.
Go to settings
> Text Replacement
> Set up your shortcut
Then, whenever you type your shortcut, in my version, I simply type ooo – then the full-text message will appear. As these short-cuts are now set up, then do not only work for text messages, they will work for emails, notes, reminders and anywhere else that you use your iPhone when writing. It even syncrosies with your Mac or Macbook and iPad – how cool is that?