In storyboard, is this the correct way to add a scrollview?
drag a view controller (comes with a view)
drag a uiscrollview on it
or
drag a view contorller
remove the regular uiview in it
and drag a uiscrollview directly on the controller
What would be the difference ?
The difference is simple. Every UIViewController has one root view (the view it controls).
Either you put your UIScrollView to the root view. Or you make the root view to be an instance of UIScrollView.