Question

why sun does not rises everywhere at the same time give reason

Answer 1

here is a sunrise/sunset 'line' extending around the Earth. This line (called the Teminator- because night or day terminates there) rotates continuously and at the equinoxes (March 21, September 22) the terminator intersects the geographic poles.

At any given moment, along one half of the terminator the Sun appears to rise - for all observers on Earth - at the same time (along the other half the Sun appears to set).

At extreme latitudes - close to the poles - the Sun does not go below the horizon during parts of the year (near one of the solstices) and does not rise above the horizon at other times of the year ( near the other solstice).

Answer 2

It does so because the Earth is round and spins on its axis, the axis is also tilted so you won’t have the same sunrise/sunset hour between things as far apart from the Equator on the same North pole to South pole line.