In Christianity, God exists in the mystery of The Holy Trinity: God The Father, God The Son and God The Holy Spirit.
In Judaism, God has several titles which refer to some aspect of God's goodness or greatness. He is most often called Yaweh.
In Islam God is known as Allah.
Because they are part of the 3 Abrahamic religions, which worship God, except they call him Allah.
The God of Abraham.
Muslims believe in God's all prophets. Every prophet come with same message in principal. But in other religions some modifications made by followers after the prophet. But there is no such modification in Islam. Islam is the God's perfected religion.
Islam, Judaism and Christianity
The three Abrahamic religions are Judaism (the Tanakh), Christianity (Old Testament), and Islam (the Taurat).
Samuel
There is only one God per the professions of the 3 largest religions. God has many names and titles in the Hebrew/Christian Bible.
The God Yahweh (english translation Jehovah) This name is found in most Bibles at Exodus chapter 3 verse 15.
1. Christianism 2. Islam 3. Other religions
The three are Christianity, Islam and Judaism. Three other sacred religions are Hinduism, Buddhism and Shintoism.
In terms of independent religions (not branches of other faiths or anything), I would say Mandaeism, Yazidism, and Cao Dai.
This is a tough question because it relies on 3 things; 1) your religious background 2) your belief of what God is 3) your views of a higher being working within life but from outside it Most Western religions that spawned from Judaism (Islam, Christianity, & modern Judaism) Believe in God as a higher power in a place outside the realm of the earthly universe. All 3 religions believe God rests in a holy place called "heaven" or in Islam "paradise" and directs the world from a view looking down on it. Eastern religions believe in a sense of morality in the human soul and the influences ones life events have over those morality thoughts. The prime example of this religious thinking are the religions of Buddhism, Taoism, and Confucius-ism. in these religions, the God figure is the morality of the human soul and ones ancestors are worshiped as tribute to their souls. The Hindu religion blends the western view of a physical god or gods with the eastern views of pure morality and the human soul. In Native American religions, Nature is the God figure and the main God is Mother Earth.