there is no diffrent in thery. but iin practice active low pass filter has a gain and very flexcible for cutoff freqency. but single rc or c lowpass filter has a finite phase shift (max 90 degree) and passive and has a loss.
your question is very general.
The difference between these two are
The cutoff frequency
passive lpf has sloping cutoff that's not good for some application
and the voltage loss
passive lpf can loss some voltage after signal had been filtered, in active you can add gain for the filtered signal