I have found now that any new app I add simply goes into the iPhone or iPad and not onto any screen as the "new norm".
So now I immediately scroll to the "library" option (as far to the right as you can go). When I see the icon (search if needed takes you to it) then hold my finger on the icon and it brings up a "selection list" of options, including "move to home screen". I select this option and it then is added to the last screen you have apps on with a space or makes a new page for it. From there you can hold again on it until the "wiggle" starts and then drag it to the left to any of your screens you desire, or have a space on and let it go. Then tap the home button (if old enough device to have a home button ) OR on a blank space on the screen and it will stop the "wiggle" on all app icons. It should now be on the desired screen for you.