If you car is a facelift W204 (2011-2014 for the saloon, 2011-2015 for the coupe), and it is equipped with Audio20, then it will most likely have the optional Becker Map Pilot navigation system that resides in the glove compartment. With this setup, importing destinations online is not possible. This is also true for the Navigation 20 system. On these cars, importing destinations online (aka sending a destination to the car) is only possible with COMAND Online NTG4.5/4.7.
If your car is a W205 (2014 onwards for the saloon, 2016 onwards for the coupe), then your Audio 20 system will have the optional Garmin Map Pilot navigation system that resides on an SD-Card. I do not know if Garmin Map Pilot supports importing destinations online - someone else might be able to help.