…can be achieved by setting our lenses to a low aperture value (a large aperture) like f/1.4 (if you don’t know how to do this, you could use your camera’s Portrait Mode).
But that is not the only way to get these blurry backgrounds. The effect can also be achieved or enhanced by reducing the distance between us and our close object. Because it is the relative distance between the close and the far that determines the far object’s blurriness.
So if I move my hand really close, as close as I can focus, then even at f/5.6 I can get dramatic blurring in the background. And that is what is happening here:
Remember that whenever you want blurred backgrounds: get close to your object, and/or zoom in on it.