You will most likely be using one of the two citation styles listed below:
The Duquesne University Writing Center has created very helpful guides to assist you with citing in-text and in bibliographies in MLA, APA, and Chicago Manual of Style. PDFs of these documents are available below.
If an author has said something in an original way, it might be best to quote them. Whenever you are using the author's exact words, you should use quotation marks.
Since you can't always use direct quotes, it is important to summarize and paraphrase. Summarizing and paraphrasing must still be cited. Even though these are your own words, you need an in-text citation and a reference in the bibliography.
Duquesne's Writing Center has a guide on paraphrasing, summarizing, and quoting:
"When in doubt, CITE IT!"