Whether it's plagiarism (or cheating) depends on the context. If you're in a class where your english ability is being evaluated in your writing, it's cheating.

Whether it's plagiarism (or cheating) depends on the context. If you're in a class where your english ability is being evaluated in your writing, it's cheating. If it's adding new ideas, its cheating. If you're writing technical reports that have no english or stylistic weighting in the grading, and you're using it solely as an advanced grammar checker and making sure all the ideas in the content are your own, then it could be acceptable.