Answer the question-

If we say that a car is moving with 50 Km/h then this is speed of that car but if we say that a car is moving with 50Km/h in North or any particular direction then it is velocity of that car.

Let an object is moving in a circular motion then its speed could be constant for example 2 m/s but here its velocity is continuously changing. Because velocity depends on direction also which keeps on changing in a circular motion.