This is by far the best online Plagiarism checker tool which you can use. Grammica is a well-known tool among writers and also who need to quickly check if the article is original or copied from other places.

If you are a professor and need to check if the research paper is original or copied from multiple sources online, this tool is perfect for you. See in the above screenshot, how easy it is to use the plagiarism feature of Grammica.

https://grammica.com/plagiarism-checker