There are many fields in Artificial Intelligence, and they are divided based on different factors, such as their goals, working, and even the applications. The subfields in the world of Artificial Intelligence are Machine Learning, Natural Language Processing, neural networks, Deep Learning, computer vision, robotics, expert systems, and natural speech processing. These are some of the important fields that have specific engineering and scientific goals. Each of these subfields in AI has a different way of knowledge representation, rule systems, and learning methodologies. But then, the other way of dividing AI systems is based completely on the applications that these systems are meant for. Be it security, transportation, piloting, or networking, there are numerous ways in which AI systems can be divided.
If you are looking for an online course to learn Artificial Intelligence, check out this Artificial Intelligence Online Course by Intellipaat.