Its a piece of written work that involves investigating an area of mathematics
NO plagiarism it should be less than 16%.
Bellow there are material that will clarify what is being asked specifically.
Here are some helpful links:
https://www.youtube.com/playlist?list=PLcvv9pSnukaVkFh_OkFceh0aD9Ov02UjV
https://nailib.com/blog/ib-math-ia