Are the words everybody and everyone interchangeable?
The short answer is, there's not much difference! Both of these words mean "every person," and in dictionaries, the meaning of everyone is often given as everybody, and vice versa.
However, it's worth mentioning that many people think everybody is a little more casual (more informal) than everyone. Also, everybody is used more often than everyone in spoken language, which makes sense if it's more informal. Having said this, it's absolutely fine to use either one. You have a choice.