According to George Lawton of TechTarget, "Generative AI is a type of artificial intelligence technology that can produce various types of content, including text, imagery, audio and synthetic data." The reason why this technology is a game changer is in the simplicity for the end users and the speed in which new content can be created. This technology is not brand new but was not as useful for the everyday end user until recently.
For more details, including some of the concerns about "deep fakes" - digitally forged images and videos, and scams and cyber attacks, to opportunities in movie dubbing, see George Lawton's article, What is generative AI? Everything you need to know.