There are many styles of citation, but they all require identification of the author and text from which you draw ideas. Once you know what citation system you are using (MLA, APA, AMA, etc.), you will still need to make decisions about how you integrate sources into your paper. The two basic methods are quotation (where you reproduce the author’s expressions word for word, placing them in quotation marks) and paraphrase (where you put the author’s ideas into your own words, but still cite the original author as the source of the ideas the words convey). In practice, these methods look like this when using APA:
In Spurious Coin: A History of Science, Management, and Technical Writing, Bernadette Longo (2000) argued that from 1850 to 1950, technical writing was the “lingua franca of engineering and scientific knowledge” (p. 1).
Technical writing was a significant form of communication among scientists and engineers in the 19th and 20th century (Longo, 2000, p. 1)
In both cases, the source of the words and/or ideas being discussed is being acknowledged. And in both cases you would include an entry for this work on your references page, which in APA 7 would look like this:
Longo, B. (2000). Spurious coin: A history of science, management, and technical writing. SUNY Press.
You can find plenty of examples on how to format these references in the various Citations and Style Guides available through SharkWrites.
There's no simple rule for when to quote or when to paraphrase. Direct quotation is usually used when the way the idea is expressed is just as important as the idea itself. Direct quotation is often easier, since all you have to do is reproduce the author’s words exactly, put them in quotation marks, and include the citation information for that source. Paraphrasing is trickier, since you have to ensure that you are only reproducing the ideas in the original source, and not how those ideas were expressed. And in paraphrase, you also have to be careful that you are ethically reproducing the ideas and not misrepresenting what the author said in any way. Here are some examples to help show you the difference.
"Technical communication, then, became the lingua franca of science and engineering" (Longo, 2000, p. 1).
Technical writing eventually became the lingua franca of engineering and science (Longo, 2000, p. 1).
Most writing by 19th-century engineers and scientists was too technical (Longo, 2000, p.1).
Technical communication eventually became the primary way that engineers and scientists communicated (Longo, 2000, p. 1).
According to Longo (2000), technical writing became the shared language of engineers and scientists (p.1).
Composing different kinds of texts (books, journal articles, web sites, etc.) can require slightly different citation formats, and different academic fields follow different conventions for quotation versus paraphrasing. Make sure to understand what is conventional in your field and for the kind of text you are composing.