Existence of God is a matter of belief and devotion. No one has ever seen God. It is our spirits and beliefs that make us feel safe when we think and pray God for good life.
In general, it is often seen, we either prepare idols of god or we see pre-existing idols in the form of stones and big rocks in some place. The question here is why would we want to pray to a random stone? Well, it is our pure intentions, dedication that makes up worship a smallest stone to largest rock in honor of worshipping God.
In Hindus, at time of crisis, it is said to chant Hanuman Chalisa, as it is believed that the bad goes away as we chant this chalisa. Our prayers are so pure, at times the bad actually goes away.
Indian history, as written in Ramayana and Mahabharata, often prove that Gods did exist, as some of its event still have evidences in current times.
Each religion has their own God to whom they worship and pray.
I hope this answer helps!😊