Install the app on the phone, then go to it in the applications menu. If there is an option for "Move to SD Card" click it and it will move the app to the card. If that button is grayed out it means the app does not have that option so you can't move it.
This has nothing to do with whether the phone is rooted or not, whether or not an app can be moved to SD is determined by the developer when they write it. Rooting helps with other things, such as being able to uninstall system apps and bloatware that are otherwise not removable.
There are apps that can make it easier to move other apps to the SD card by listing which ones are in fact moveable, but none that will allow you to move ones that did not originally have the option.
