Question

what is lenght of observable univers ​

Answer 1

The comoving distance from Earth to the edge of the observable universe is about 14.26 gigaparsecs (46.5 billion light-years or 4.40×1026 meters) in any direction. The observable universe is thus a sphere with a diameter of about 28.5 gigaparsecs (93 billion light-years or 8.8×1026 meters).

Answer 2

ACTUALLY WE ARENT ABLE TO SEE EVEN THE OBSERVABLE UNIVERSE CLEARLY.....WE ONLY SEE THE UNIVERSE AT NIGHT FILLED WITH 100'$ OF STARS BUT WE CAN'T SEE THOSE BEAUTIFUL GALAXIES AND SUPERNOVAS AND nebulae that are spread all over the universe.. so I will say the length of both OBSERVABLE and unobservable universe to be
$\infty$