The Below depicted Demographic Map gives a simplified overview of the World and the distribution of Religions across its Continents.
First and Foremost are the Main 4 Religions of Christianity, Islam, Hinduism and Buddhism. Of these the various sub-divisions are roughly depicted.
Islam is mainly found in the Middle-East, North Africa, Central Asia and South-East Asia with its most populous nation in Indonesia. In by far most Islamic Regions Sunni Islam is the dominant sub-division, with Shia Islam only widely practiced in Iran (Persia) and (parts of Eastern) Iraq. In China Islam is spread thinly throughout and concentrated in the North-West. The rare form of Wahabism can be found in Saudi Arabia and lately in Indonesia and other Saudi "Aid" Nations. There are many sub-divisions and streams of thought within Islam itself.
Various sub-divisions of the Christian Faith can be found throughout western Europe (although in many citizens have no affiliation with any church and are atheist or other), throughout South-, Middle-, and North-America. The South of Korea and the Philippines also have a significant Christian (Catholic or Protestant) population group. A last Continent with a significant population of Christians is Australia, mainly in the urban and rural sections on the East Coast of the Continent.