If you've updated your iPhone or iPad to iOS 11.4 you've got a new feature: Messages on iCloud. What does that mean, you might very well ask? Well, it's a bit complicated, and David Pogue explains it all in this link:
https://finance.yahoo.com/news/messages-icloud-landed-turn-191908351.html
I must admit -- this is something I'm not too excited about, but it may be helpful for people who use text messages and iMessage a lot.
Jim Hamm