Extensive use of AI provides the intelligence to the 6G communications and networks. The AI enabled design and management will be crucial to optimize 6G communications and networks and improve their performances. The AI algorithm will be a key enabler to enhance 6G communication and network performances, reduce the complexity of key 6G functions and optimize the configuration and operation of 6G. The 6G performance improvement by AI techniques is no longer a burning issue. The issues are how and where to adopt AI techniques in 6G communications and networks. In this chapter, we introduce key criteria for AI enabled 6G communications and networks and discuss the approaches how and where AI techniques can be used in 6G communications and networks.