Classification is a process related to categorizing or labeling data based on features. It is a supervised learning technique in machine learning where the goal is to assign predefined labels to new observations based on their attributes. Common applications of classification include email spam detection, image recognition, and medical diagnosis. Algorithms such as logistic regression, decision trees, support vector machines, and neural networks are used to build classification models that can accurately predict the category of unseen data. Effective classification models help automate decision-making processes and provide valuable insights into large datasets.