The typical interpretation is that the observer has a special quality - the ability to cause the quantum wave function to collapse from a wide range of possibilities to one single reality. Reality as a single thing only crops up when you have some entity capable of perception entering the picture.
For hundreds (I think thousands) of years, humans have posited that free will, as such, depends upon being "self aware" - you cannot have a will if you don't have some concept of a self separate from the rest of the universe. To be aware of the self, you must of course, be able to perceive the self.
And now you can probably see where I am going - free will then comes in as being able to collapse the QM waveform of your own mind!
I hope that is sufficiently scientifically mumbo-jumbo for everyone concerned