On the new iPhone 10 any of them can you have more than one screen open at a time?

On the new iPhone 10 any of them can you have more than one screen open at a time?

What do you mean more than one screen? If you're talking about having multiple apps running in the background, yes, it's been possible for many years.

Technically yes, but you can only use one at a time.

Are you on about split screen? Yes the iPhone X and even the iPhone 8 can do split screen

Not currently no. That may come as part of iOS 13 though (my speculation).

If it does it could be on the 6, 7, 8 (the Plus models & their S Plus models) XR & XS Max (& their 2019 successors)

You can't see them side by side like on the iPad yet, but the double-click that brings up the task switcher has been replaced and enhanced by finger swipes. In the 'gesture area' at the bottom, slide left or right to switch apps fast, or slide up and hold to bring up the cards representing opened apps.

Its possible