The charger that comes with the car is a level 1 charger that will operate 0n 115V or 230V. There are many threads on the website about using it on 230V and how to make an adapter. Operating on 230v halves the charge time. A level 2 charger with 30A capability reduces the charge time by a factor of four or five.
The actual charger is within the car. The level 1 or 2 charger is actually an electronic unit that tells the car what current level to charge at, provide safety sensing and switching the power on/off. The car's charger cannot charge at more than 30A.
You will also see discussion about extension cords. It is important to get one with very good quality plug and socket since that is where all extension cord failures occur.