with the ball being passed backwards (away from the line of scrimmage). That's it. That's all. The center can snap it between his legs, pick the ball up and hand it backwards to the QB, throw it overhanded to a WR, toss it underhanded to a RB, throw a bounce pass to he slot receiver, throw it over his head with hands, etc. As long as the center passes the ball backwards, it is a legal start for a play from scrimmage.
These days, the most common occurrence of this sort of play in college is when the defense is caught napping on a PAT. The offensive team will huddle outsidee of the hash marks, the center will break from the huddle first, go pick the ball up, and throw it over to the other 10 guys still huddling. If timed correctly, this usually always ends up in a two point conversion.