Proceed only after you have a completed, correct works cited list/bibliography.
For MLA citations, read on! 
How to credit sources WITHIN your paper
ALL quoted and paraphrased information MUST be cited. Anything that didn't come from your own brain must be cited.
In-text/Parenthetical citations have shortened source information in parenthesis at the end of the sentence.
For example:
Romantic poetry is characterized by the “spontaneous overflow of powerful feelings” (Wordsworth 263).
You may also choose to include source information (author and/or article title) within the sentence. Any information you add in your sentence does not need to be repeated in the in-text citation. Use signal phrases (see bottom of the page) to let the reader know that source information is embedded in the sentence.
For example:
Dr. Hatzenbuehler, history professor at Idaho State University, points out that "popular sovereignty may be antithecial to fundamental rights" (370).
When there's a page number, put it in parentheses.
For example:
Wordsworth stated that Romantic poetry was marked by a “spontaneous overflow of powerful feelings” (263).
Wordsworth extensively explored the role of emotion in the creative process (263).
For APA citations, read on!
In-text/parenthetical citations include...
Short quotation examples:
According to Jones (1998), "Students often had difficulty using APA style, especially when it was their first time" (p. 199).
Jones (1998) found "students often had difficulty using APA style" (p. 199); what implications does this have for teachers?
Long quotations (40 words+, block indent, leave off quotation marks)
Jones's (1998) study found the following:
Students often had difficulty using APA style, especially when it was their first time citing sources. This difficulty could be attributed to the fact that many students failed to purchase a style manual or to ask their teacher for help. (p. 199)
Paraphrases:
According to Jones (1998), APA style is a difficult citation format for first-time learners.
APA style is a difficult citation format for first-time learners (p. 199).
Resources:
Via OWL Purdue.
FAQs for APA In-Text referencing
Signal Phrasing lets you weave source information into your sentences. This is a super scholarly way to cite.
MLA In-text citation examples
APA: it's most common to put the author's name in the text and use parenthesis only for dates and pages.
Signal phrases don't always have to be at the beginning of a sentence. Vary the ways you use signal phrases to add sophistication to your writing. The basic formula is NAME + QUALIFICATIONS + LOCATION (if applicable) and a VERB. Avoid use of "said or says" - it's seen as a weak verb.
When using signal phrases, you may add extra source information to add credibility (or to highlight possible bias).
For example:
As quoted in an article from New Scientist, XYZ person countered, "blah blah blah...."
Click & Scroll for the signal verbs list
