Question

every one is telling that hydrogen + oxygen is water but in our surroundings also there so many hydrogen and oxygen then why it is not forming as water

Answer 1

Yeah, that's because hydrogen and oxygen are not present in correct amount to form water. The chemical equation for water is H20 and in the atmosphere oxygen is high and hydrogen is very low. As the amount of hydrogen molecules are not 2 and the oxygen molecule is not exactly 1, they are not forming water.