Plagiarism is misrepresenting another's work as your own. This could be taking someone else's paper entirely or by taking bits and pieces of from it. Plagiarism isn't limited to papers, it could be anything that could be any form of media or ideas that are published or unpublished. Published works come from journals, newspapers, media sharing platforms, or similar places. Unpublished works are works that are not yet published, drafts, or assignments from previous or current semesters from another person.
Using your own work will greatly reduce your risk of running into plagiarism. Citing correctly will also help eliminate plagiarism. For help with citations, visit our page on citing here (link).
Common knowledge is information and facts that do not need to be cited. These are things like dates, locations, and historic events. Common knowledge things are things that can be found in many independent sources.
If you are still unsure, you can still cite! It is better to cite something than to not cite something and be wrong.