Poly in means , means a same thing is known by different name

Lets take a example here

class Animal;

virtual function AnimalType();

$display(“ Welcome to Type Animal”);

endfunction

endclass

class Dog extends Animal;

function AnimalType();

$display(“Welcome to Dog Animal Type”);

endclass

class Cat extends Animal;

function AnimalType();

$display(“Welcome to Cat Animal Type”);

endclass

class Horse extends Animal;

function AnimalType();

$display(“Welcome to Horse Animal Type”);

endclass

program

main

AnimalType ET;

Dog D1;

Cat C1;

Horse H1;

initial

begin

ET= new();

ET.AnimalType();

D1= new();

ET= D1;

ET.AnimalType();

C1= new();

ET=C1;

ET.AnimalType();

H1= new();

ET=H1;

ET.AnimalType();

end

endprogram

what would be result

Welcome to Type Animal

Welcome to Dog Animal Type

Welcome to Cat Animal Type

Welcome to Horse Animal Type

what did you see here same Animal Type class have different output , it means same things represented in many form , hope it helps you to understand polymorphism

So polymorphism is concept of OOP , now use of this depends on such functionality requirement

polymorphism is achieved by declaring function/ task as a virtual