The Buddha is Siddhartha Gautama, who left a palace, sat down under a pipal tree and woke up, and then spent forty-five years teaching a path out of suffering rather than a doctrine about himself. He is not a god in the Buddhist account, and is venerated across traditions as the teacher of gods and men.
Modern Practice
The Buddha is present in practice rather than in petition: sitting, breathing, watching the mind, and acting with compassion. He is called on at Vesak and at the beginning of a retreat, and his instruction is to test the teaching rather than believe it.