Classification forms a very important topic in Data science. It is used widely in many applications.
Classification is labelling. For example, you can look at all the vehicles on the road a label them as “Cars” or “Bikes” or “Trucks”. Here we classify the objects into categories.
Classification in the real world
Medical Diagnosis Diagnose diseases like Cancers, where classification is used to know if a tumor is malignant or benign
Sentiment Analysis Classification can be used to analyze if a text/review/tweet is positive, negative or neutral.