This is the most obvious type of plagiarism, so I call it the "Copy-and-Paste Facepalm," and it can happen with or without the assistance of AI. It is plagiarism to copy the text generated by AI into your paper and present it as your own, and it is plagiarism if you copy and paste from any source, such as a website, without using quotation marks and a citation. One exception is short, common phrases or the proper names of things or places, but anything longer than four or five words generally should be put in quotation marks.
Below you can see how to correct this issue in MLA format using three things: quotation marks, an MLA in-text citation, and an MLA full citation.