Merriam Webster defines Plagiarism as “the act of using another person's words or ideas without giving credit to that person”.
Whether the product of your research is shared in print or in an oral presentation, you should include both in-text and bibliographic citations. You must also cite any images that you use, as well as charts, videos, audio recordings, and other works; if someone else created the content, the source of that content must be cited regardless of the medium in which it appears!
Aside from helping you to avoid plagiarism and to satisfy the requirements for the assignment, proper citations also:
EasyBib. “Determining What Is Plagiarism?” EasyBib, Chegg, 1 Jan. 2021, https://www.easybib.com/guides/plagiarism-guide/what-is-plagiarism/.
Merriam Webster Dictionary. (n.d.). Plagiarism definition & meaning. Merriam-Webster. https://www.merriam-webster.com/dictionary/plagiarism#note-1
Citation is simply telling your reader - in an organized way - what resources you used to write your paper, and giving enough information so your reader can find it themselves, know where to look in it to find the same info you did, and credit who created those resources.
You will use different styles of citation - such as APA or MLA formats - but these are exactly that: styles. In any citation style, you are always trying to credit your resources and provide your reader the means to find them.