In the Islamic world, less than 20% are Arabs. The largest population of Muslims live in non-Arabic countries, such as Indonesia, Bangladesh, Pakistan, and India.
It is believed that most Arabs are Muslims, but it is a misconception. There are millions of Arab Christians, Druze, and Jewish Arabic communities. It is worth mentioning that 93% of Arabic communities are Muslims. So It is important to make this distinction to understand that the most majority of Muslims are not Arabs.