Machine learning is a branch of AI that allows computers to learn without being explicitly programmed. There are three main types of machine learning: supervised learning which uses labeled examples to learn a mapping between inputs and outputs, unsupervised learning which finds patterns in unlabeled data without target variables, and reinforcement learning where an agent learns through trial-and-error using feedback from its environment. LearnBay is a data science institute in Bangalore that provides machine learning and data science training and certifications.