Car: Burj Khalifa is located near Dubai Mall, so you can reach the observation deck at the top of the tower by car, where you can leave it in the free Fashion Avenue parking, which is located on the lower floor of the shopping mall opposite the food court.
Public transport: You can reach Burj Khalifa by public transport via the metro. You need to get off at Dubai Mall/Burj Khalifa station, then walk across the air-conditioned overhead bridge, then head to the ground floor where your final stop will be Burj Khalifa.
Taxis: Any taxi can take you from anywhere in Dubai to Burj Khalifa easily and quickly.