Even though it’s a star, you won’t see the sun on any of the star maps in our books. That’s because to us on Earth, the sun seems to move through the sky from one constellation to another. The sun is not actually moving through the constellations, it just looks that way from our moving planet.
You can’t observe constellations when the sun is in the sky because the light from the sun overwhelms, or blocks out, the light from all the other stars. The sun is much closer to Earth than any other star, so the sun’s light looks much, much brighter than the light from other stars.