Machine learning makes computers more intelligent without explicitly teaching them how to behave. They learn based on experience, which in this case is huge volumes of data. ML is one application of AI based around the idea that we give computers access to data and they learn for themselves.
Whether we realise it or not, we have all experienced machine learning (ML). Think about Google maps suggesting the best route to travel or your internet browser showing you what you just may want to purchase based on previous purchases. It is a pervasive technology that is all around us and gaining more and more traction.