Plagiarism is unacceptable for academic situations. The internet has made it easy to research material for academic papers but it can easily lead you into plagiarism trap. All information on various websites has an author. You should track everything and give credit. Professors will believe that you tried to get credit for ideas by other people if you use information from electronic documents in your paper and fail to accredit the source document and authors.
Do not copy your dissertation content from classmates, whole passages from articles, books, journals or other published work without citing. It is important to begin dissertation early. When you start late, you might be tempted to borrow ideas from someone or buy a complete paper from the internet without knowing whether has plagiarized sections.