This guide reflects the latest version of the APA Publication Manual (i.e., APA 7), which was released in October 2019. The equivalent resource for the older APA 6th edition style can be found here. 
 

What's New in the Seventh edition?

The following are examples of new and updated guidelines. For a more comprehensive overview of content changes, read the Publication Manual of the American Psychological Association, 7th Edition Introduction or visit the APA Style website. 

• the presentation of digital object identifiers (DOIs) as URLs has been standardized. Both are presented as hyperlinks; the label "DOI:" is no longer used, and the words "Retrieved from" are used only when a retrieval date is also needed.
• the number of authors included in a reference entry has changed; up to 20 authors are now included before names are omitted with an ellipsis.
• journal article references always include the issue number, and book references now omit the publisher location.
• in-text citations have been simplified; all in-text citations for works with three or more authors are shortened to the name of the first author plus "et al." (except where this would create ambiguity).
• Audiovisual materials receive expanded coverage, with new examples for YouTube videos, PowerPoint slides and lecture notes, TED Talks, and more.
• the singular "they" is endorsed, consistent with inclusive usage and existing guidance on age, disability, gender, racial, and ethnic identity and sexual orientation has been updated to reflect best practices.
• JARS (journal article reporting standards) are a set of guidelines designed for journal authors, reviewers, and editors to enhance scientific rigor in peer-reviewed journal articles. These standards provide guidelines for authors on what information should be included, at minimum, in journal articles.

APA formatting is based on citing scholarly journal articles. All reference list citations follow the same basic format: 

who-when-what-where

For scholarly journal articles, this means: 

who = author 

when = date

what = title of the article

where = name of journal, volume, issue number, page numbers, doi

Here is a sample reference list citation: 

Here is are some examples of how to cite this source in text: 

Drapalski et al. (2011) found....

...as a recent study concluded (Drapalski et al., 2011). 

While the specific elements will differ based on what you are citing (book, book chapter, website, blog, etc.), they all follow this same order. The tabs above provide guidelines for citing different kinds of sources.