Whenever you use an idea or information from a source, you need to cite it within the text of your paper as you write it. In APA style, this is usually done by inserting a parenthetical citation at the end of the sentence in which you used the source. Within the parentheses, you should include the author's (or authors') last name(s) and the publication date.
(Johnson and Novak 2019)
For more information, see In-Text Citations by the Online Writing Lab (OWL) at Purdue University
In APA style, a complete citation for each of the sources that you use needs to be listed at the end of the paper on a separate page title, "Reference List." The citations should be listed alphabetically by the last name of the first author. If there is no author, then use the first word of the title (excluding articles like "the" or "a").
For additional information, see Reference List by the Online Writing Lab (OWL) at Purdue.