Developed by the Modern Language Association, this style is most widely used for research papers in the humanities. Typically, professional researchers in these fields must also write in this style in order to have their work published.
From Purdue OWL's MLA Overview and Workshop:
Using MLA Style properly makes it easier for readers to navigate and comprehend a text by providing familiar cues when referring to sources and borrowed information. Editors and instructors also encourage everyone to use the same format so there is consistency of style within a given field. Abiding by MLA's standards as a writer will allow you to:
Online citation builders are helpful when you are in a rush and have a small number of sources to manage. Typically, citations are not saved and cannot be exported to a word processor using the free versions of these tools. You can copy and paste a formatted citation into your document. Use the links below to try some free tools.
Citation software like Zotero and Endnote are more time consuming to learn but extremely useful for saving and organizing larger, more complex collections of sources and their citations. For smaller projects, you may consider emailing articles you've found to yourself as a means of archiving them.
No citation manager is perfect - though they are a great way to start, you should always double check to make sure your citations are correct.
Not sure what citation management software to use? Check out PennState's Citation Tools Comparison Chart to see how Zotero, Mendeley, Endnote, and Endnote Basic compare!