Why Cite?
It gives proper credit to the authors of the words or ideas that you incorporated into your paper.
It allows those who are reading your work to locate your sources, in order to learn more about the ideas that you include in your paper.
Citing your sources consistently and accurately helps you avoid committing plagiarism in your writing.
When to cite?
If the idea wasn't yours, you need to cite it!
Direct quote
When you paraphrase or summarize ideas, interpretations, or conclusions that you find in a source.
Using an idea that influenced your work
When you include information that isn't common knowledge
Any time you use facts, statistics, dates, or unoriginal information.
Plagiarism
All of the following are considered plagiarism:
turning in someone else's work as your own
copying words or ideas from someone else without giving credit
failing to put a quotation in quotation marks
giving incorrect information about the source of a quotation
changing words but copying the sentence structure of a source without giving credit
copying so many words or ideas from a source that it makes up the majority of your work, whether you give credit or not
From: https://www.plagiarism.org/article/what-is-plagiarism