APA (American Psychological Association) citation style requires you to note in the text of your paper every time you borrow information from a source, whether you quote, paraphrase, or summarize. In-text citations are brief and are used in conjunction with a References list with more complete information about your sources.
For more information consult: Cite Your Sources: APA Style.
The Publication Manual of the American Psychological Association is the ultimate source for using this citation style.
When you cite you indicate that information is borrowed from a source. You need to do this every time your borrow information.
Why do you cite?
There are several online "engines" where you can enter information about your source and generate a citation. In addition, some databases offer help in generating formatted citations. Caution! While these tools may save time, they usually do not generate error-free citations. You need to check the citations carefully using the The Publication Manual of the American Psychological Association, 6th edition, or another reputable source based on the Publication Manual.