The main rotor can rotate in one direction or the other depending on the manufacturer. This has no impact on performance or security. If you look at the rotating main rotor from above and it turns anti-clockwise to the left, then the helicopter is usually from an American manufacturer. If the rotor turns clockwise to the right, then the manufacturer is most likely based in Europe. This is roughly comparable to a steering wheel in a car on the right or left side.
The direction of rotation of the tail rotor is independent of the direction of rotation of the main rotor.