Overloading and Overriding both are example of polymorphism. Overriding is dynamic polymorphism while overloading is static polymorphism.
Overriding: Overriding is a changing of behavior of a class in drive class using dynamic polymorphism. for example in C# you have a class A and another class B drive from A. Class A have a virtual method abc and in class B using override you given new functionality to this method.
Overloading: Overloading is a mechanism by which we can have two different methods using same name.
Overloading can be implemented using Different parameter data types, different number of parameters, different order of parameters.