This can best be understood by drawing a number of dots on the surface of a balloon and blowing it up. Notice how the distance between the dots increases as the balloon inflates. From the viewpoint of any dot on the balloon, it looks like all the other dots are receding away from it. Our universe works in a similar way. You can imagine space-time as the balloon and the galaxies as the dots stuck on the balloon.
Every galaxy then sees other galaxies speeding away from it.
The exact value of the Hubble constant still remains controversial among astronomers. The discovery of Hubble s Law is one of the greatest discoveries in history because it tells us that our universe as a whole is expanding. You might think that Hubble's Law places us at the very center of the universe, as all galaxies move away from us in every direction.