They are interchangeable,yet there is a slight distinction. When you say for example: "Everyone in the classroom stands up." Here you refer to every individual, emphasizing on every person in the room doing the action separately. "Everybody stands up." is on the other hand more collective, emphasizing on the individuals acting together.

The two terms are essentially synonymous. Meaning they are just the same. Everyone is more sophisticated than Everybody. So you can use either anytime where you feel like it's right.

If u use everybody then u mean on all of people in some room, but if u say everyone then u mean on every one individual.

Everybody and everyone mean the exact same thing and refers to "all people".