I notice that you call God "it". This is important, because the fact that he is an intelligent being shows how we know about him.
People believe in God because God makes himself known through his works. Also, because just like a house is constructed by someone, the one who constructed all things is God. Thirdly, a real, ultimate Creator, by definition, has to be uncreated, so there must be only one.
Accepting that the universe came into existence by an intelligent designer makes far more sense than to believe that it came about through undirected natural processes, because nothing does not produce something on its own. Things don t think, or plan or figure out the best way to do anything. It takes a mind to do this, a mind with intentions, reasons and a purpose. And with what we can observe about the universe, a Creator must have a lifespan that is much longer, and power that is far greater than what we see here.
These very logical deductions have been made by the majority of humans. The details differ, but this is one reason why we must search for the true God, humbly, sincerely, and respectfully. Those who search for him can find him. And he is not far off from each one of us.