In-text citations are exactly what they sound like. They are citations that appear in the text of your essay. In-text citations are important because they immediately let the reader know when you are including information that you got from somewhere else. They also let the reader know who/where the information came from.
In-text citations are short, and will direct the reader to a longer reference in your Works Cited at the end of your paper.
Most information you include from outside sources in an MLA paper will be direct quotes. These should always appear in quotation marks, with your in-text citation after the quote: 
Even when you state a piece of information in your own words, you will still need to cite it if the information is not common knowledge. This is called a paraphrase. Make sure your paraphrases are not just a mashup of synonyms from the original source, but a genuine display of your understanding of the information. Paraphrases will generally refer to an entire page, scene, or portion of a source:
Citations have two elements: author and page number. The author’s last name and the page number(s) where the quotation or paraphrase came from must appear in the text of your paper. There are a couple different ways you can format your in-text citations:
Above: The author’s name appears in the text of the sentence, and the page number for the quotation is in brackets at the end.
Page numbers should always appear in brackets immediately following the quotation or paraphrase.
Above: The author’s name and page number appear in brackets at the end of the sentence. This is also an acceptable way
to provide an in-text citation.
*Note that there are no commas or "p." as there is in APA.
Above: Since this quotation is from a poem, include line numbers instead of page numbers. The slash (/) indicates a line break
in the poem.
Be sure to also keep all punctuation that appears in the poem (periods, question marks, capitalization, etc.)
Above: When quoting a film, include a timestamp instead of page numbers. In the example above, the quote lasted from
1 hour, 47 minutes, and 48 seconds into the film until the 1 hour, 47 minute and 5 second mark.
Above: Indirect quotes (quotes from a source within another source) should be preceded by the quoted author's name. In the brackets, write "qtd in" then add information for the source you actually read. In this example, Chen et al. is the source that will appear in the Works Cited list.
*It is best if you can find the original source that the quote is from so that you can read and cite it directly. However, indirect quotations are allowed when no other option is available.
*If you are citing a source that doesn't fit to these standard citation rules, consult your MLA handbook or another reputable source, such as Purdue University's MLA Guide. They provide more in-depth details on how to create in-text citations for a variety of source types.