While writing your paper, the citation to the source you took the information from needs to be obvious to the reader. The reader needs to understand which information you took (are referencing) and how to find that information. To make this as obvious as possible, the citation goes in the same sentence that you mention the source and information. Depending on the style you use, it will look slightly different, but the rule is always the same. Place the citation within the same sentence, before the period that ends it. In-text citations are different from footnotes and endnotes that use symbols or numbers to reference the source. In-text citations use the author's last name as it appears on the final references or works cited list.
MLA requires page numbers of all citations whereas APA only requires page numbers for direct quotes.