if you need configure it on your desktop - just install any QtCreator version and add new Kit via settings, then configure it with compiler from cross tools you've used to build Qt fro RPi
But if you need it on RPi - I'm afraid you will have to build Qt right on RPi first
Ok, how do I do that, so far I've got a working 5.7 on the PI which as cross compiled. Last time I tried to install QtCreator on the Pi it completely screwed up the Qt build on the Pi, I had to start over.
with crosscompiled Qt you can't use QtCreator with this Qt on RPi (as I know)
just google how add crosscompile kits to QtCreator