The biggest difference between the two styles is how authors are acknowledged in the text. Both styles require that you acknowledge the author or authors in the text when referencing an author's work or source material. However, APA uses the "author-date" system whereas MLA uses the "author-page" system of citation. In APA style, you cite the author's last name and the year of the publication from which your reference is drawn. In MLA style, you cite the author's last name but include the page number of the work you are referencing.
Each style handles parenthetical citation formatting a little differently. Although using an author-date system versus an author-page system may appear to be the only difference, the two styles differ in how the information is set off in parentheses. In APA style, you list the author's last name, followed by a comma, followed by the year of the work. In MLA style, you list the author's last name, followed by a space, followed by the page number. When citing two names, in APA style, you use an ampersand between the two author names but in MLA, you use the word "and" between the two authors.
Both styles require a bibliography at the end of the paper that list all the works cited in the body of the paper but each style formats the information differently. In APA style, the bibliography is called "References" and in MLA style, it is called "Works Cited." Begin the bibliography page by centering the respective term at the top of the page before listing the works. Both styles begin the first line of each citation at the left margin and indent each subsequent line.
Alphabetizing can be somewhat tricky. Both styles alphabetize the references using the first author's last name. In APA style, if there are multiple works by the same author, the works are cited in chronological order from earliest to latest. In MLA style, the works are cited in alphabetical order by title. In addition, once you list the author name for the first work, each subsequent work uses three dashes to indicate that this is the same author.