ChatGPT plagiarizes by copying other people's work. It does this by storing what it reads from people and conversations, and then using it. Basically, ChatGPT looks for ways to copy and paste other people's substance and present it as its own. It does this by grabbing text from all kinds of places, such as websites, books, and articles, and then using those words to create something new. In other words, ChatGPT has a large database stored with words, sentences and phrases that it can use to create its own work, which can sound like it was written by a human.