Something perforated usually contains a series of tiny holes. You might see a perforated line on a utility bill, where you are supposed to tear off that part to mail in with your check.
Anything with holes can be said to be perforated, especially if the holes are in a row or series. You wouldn't say something with one hole is perforated. This word can have some grim uses, like if you're talking about a murder victim whose body was perforated with bullets.