Mohammedan is an old term that some people used to describe followers of Islam, which is a religion originally started in Arabia by a man named Prophet Muhammad. It's important to know that many people find the term Mohammedan to be offensive nowadays, because it implies that the religion is all about a single person - which it isn't.
Islam has over 1.8 billion followers all over the world, and they believe in one God, Allah, and the teachings of Prophet Muhammad as explained in the Qur'an. Muslims (followers of Islam) follow certain rules and rituals, such as praying five times a day, fasting during Ramadan, and giving to charity.
Muslims believe that they should be kind, honest, respectful, and helpful to everyone around them. They also believe in taking care of the earth and treating animals gently. Overall, Islam is a religion that emphasizes peace, love, and compassion for all people.