Where do deleted text messages on an I-phone go and can they be recovered and/or permanently deleted? Thanks.
http://www.macworld.co.uk/how-to/iphone/how-retrieve-deleted-text-messages-on-iphone-sms-3636380/ and https://discussions.apple.com/thread/2594591?start=30&tstart=0
If you happen to have Messages.app on a Mac, they aren't automatically deleted from there. And the other party's copy won't be deleted either. Of course Apple iMessages and SMS via the Messages app are handled differently from an encryption/security perspective.
There are aftermarket utilities that can recover deleted texts from an iPhone. This is the one I used after I accidentally deleted some texts. It didn't do a perfect job but it was good enough. That was in 2014 so maybe the software's improved since then.
Of course, if you use an application like Messages.app, things will get easier. However, if you don't do this, it means you can only retrieve the iPhone deleted text messages through the recovery tool and there is no other option. Also, before you start using the data recovery tool, you need to stop using the iPhone in order to ensure that you can retrieve deleted text messages.