The entire point of parenthetical documentation is to properly credit information and ideas to the original creator. Knowledge is built upon the work of others and it is important to be able to trace back ideas and the development of information and knowledge. In addition, not only is it just courteous to give credit where credit is due, it is also a serious ethical matter in academics. Failing to cite your sources, the places you got the information, ideas, etc. constitutes a form of plagiarism.
To avoid plagiarism, provide appropriate credit to the source whenever you:
Paraphrase the ideas of others
Directly quote the words of others
Refer to data or data sets
Reprint or adapt a table or figure, even images from teh internet that are free or licensed in the Creative Commons
Reprint a long text passage or commercially copyrighted test item
To properly give credit using APA, there are two elements that you must complete: parenthetical documentation via in-text citations and the reference list. The in-text citations are how you acknowledge inside your own writing when you're referencing sources of information, ideas, and knowledge that is not your own. The reference list is where you provide additional details about each of those in-text citations so other readers and researchers can trace back the development of your own ideas.
Each of these have rules that make up the APA citation style. The reference list and in-text citations are typically made up of four elements. We color coded them so you can see how each reference is created for in-text citation and reference lists.
Author (in purple)
Date (in blue)
Title (in yellow)
Source (in green)