Every document should be unique even though the content is the same. But how is this possible? it is possible as on every topic, every person has their own views and this subjectivity in views makes the content different. But even then, content could be the same because two people could get the same idea to write, and in this situation people get stuck. But how will one find out, whether the content written by him/her is different from others or not? So for this, there are a number of tools/websites available where you can compare your documents with others to find out how real your content is. But there is still a way to write a unique document.