First, be sure that you are using the most current APA style guide—APA Publication Manual (i.e., APA 7), which was released in October 2019.
Your best online source is the Purdue OWL APA Guide which is regularly updated.
In-text Basics
APA uses the author-date method of in-text citation. This means that the last name of the author(s) and the year the source was published are listed in parenthesis following the quote/paraphrase.
Unless you are referencing an idea or an entire work, include the page number where you found the quote/information you are using.
Like this: She stated, "Students often had difficulty using APA style" (Jones, 1998, p. 199), but she did not offer an explanation as to why.
If you are citing multiple sources in one sentence, list all of the author-date citations together, at the end of the sentence. Put semicolons between each citation and list them in the order that they would appear in your reference list: (Lambert, 2011; Smith, 1998; Zello, 2004)
In-text Citations with Multiple Authors:
If a work has two authors, list both in the order they are listed on the source. Use an & between authors:(Higgledy & Biggledy, 1942)
If a work has three or more authors, list the first author's name and then "et al": (Primo et al., 2007)
Bibliography Citations:
The Purdue OWL APA Guide provides detailed instructions, by source type, for formatting your citations. Be sure to consult either this online guide or a copy of the APA Publication Manual to ensure you are using the correct format for your specific source type
The basic formats include:
Book: Author, A. A. (Year of publication). Title of work: Capital letter also for subtitle. Publisher Name. DOI (if available)
Article: Author, A. A., Author, B. B., & Author, C. C. (Year). Title of the article. Title of Periodical, volume number(issue number), pages. https://doi.org/xx.xxx/yyyy
Webpage: Lastname, F. M. (Year, Month Date). Title of page. Site name. URL