Joining Writing Sites

People have different reasons for joining these sites. However, most of them probably want to earn extra money from writing artcles of their own. All the writing sites hate plagiarism. And those who do plagiarism, their articles shall be disapproved. If we look up the meaning of plagiarism, it means a lot of things. One of them is any publication of another author's "language, thoughts, ideas, or expressions," and the representation of them as one's own original work. If, for example, you use the source of articles written in other languages and make some modifications of the information, will you be considered to do plagiarism? Or probably writing sites only forbid writers from copying the entire articles without making any changes? I am sure you come up with further detailed information regarding plagiarism.