Citing a reference within the text of your paper is called an "in-text citation." You must cite your references both in your reference list and in the text of your paper where that source is used. You will present the information from your source in your paper as either a direct quotation or paraphrased (re-written in your own words). As a rule, "cite only works that you have read and ideas that you have incorporated in your writing" (ALA, 2020, p. 235). You do not need to cite common knowledge, that is, information that most people know or established facts.
Always provide in-text citations for the following:
Quotations and paraphrases of other sources.
Facts and figures that are not common knowledge.
Tables and images, even if they are open source.
Things to keep in mind regarding in-text citations:
Except for literature reviews, usually one or two resources is enough for each piece of evidence. Literature reviews require as many as is necessary.
You do not need to re-cite the same resource over and over in sequential sentences. Cite a resource after the first sentence in which it is used and again after a different resource is used, unless it is unclear.
It is not usually necessary to cite whole websites, periodicals, or common software or apps when they are mentioned in the text.
Not properly citing a resource is considered plagiarism.
A resource must be credited even when it is not published, e.g. an interview, email, text message, etc., but only in-text (not in your reference list).
If you are referencing your own work, you need to cite yourself.