Encyclopedias are great as sources of background information. This makes them excellent places to begin your research on a given topic, but certainly not the only place you would look for information. Most university professors will want you to use academic sources in your essays and research papers, so using an encyclopedia as a source might lead them to believe you haven't done very extensive searching and reading on your topic.
Any time you use an external source, whether it's a research article, a website, a tweet, or an encyclopedia article, you'll need to cite it. So, if you have used information from an encyclopedia, you must provide a citation and reference. But know that your professor likely expects you to expand your research beyond that.
For more advice on assessing the quality of sources, check out our guide to finding scholarly sources.
