If you are referring to the __init__ method, this is the constructor method of Python classes, meaning it is invoked when you create an instance class and it "builds" the instance that you created using its own implementation. for example,
self.name = "Sophie"
new_cat = Cat() # This is where you create an instance of the Cat class, the __init__ method is invoked setting the name attribute to "Sophie".
print(new_cat.name()) # This will output "Sophie" thanks to the constructor method setting this object's name to "Sophie" when the object (or instance) was created.
__init__, popular called dunder init(majorly because it has two underscores as a predix and suffix) is used to set up instantiation logic for each object run in a class
It's like a kind of self built-in method in every class definition that runs implicitly when u instantiate an object of a class
You don't have to involve this method explicitly. It calls itself to action when u run an object of a class
I hope this help Fariha Falaq