In Unsupervised Learning, the machine uses unlabeled data and learns on itself without any supervision. The machine tries to find a pattern in the unlabeled data and gives a response.
Unsupervised learning can be further grouped into types:
Source: https://www.simplilearn.com/tutorials/machine-learning-tutorial/supervised-and-unsupervised-learning#difference_between_supervised_and_unsupervised_learning