Objects are real world entities. Anything you can describe in this world is an object. Classes on the other hand are not real. They are just a concept. Class is a short form of Classification. A class is a classification of certain objects and it is just a description of the properties and behavior all objects of that classification should possess.
Class is a like a recipe and the object is like the cupcake we bake using it. All cupcakes created from a recipe share similar characteristics like shape, sweetness, etc. But they are all unique as well. One cupcake may have strawberry frosting while another might have vanilla. Similarly, objects of a class share similar characteristics but they differ in their values for those characteristics.
A class is defined using the class keyword in python. For example, the below code creates a class called Mobile without any attributes or behavior.
class Mobile: pass