When are in-text citations used in academic writing?

you have too sight the last name of the author and  the page number whether it is a quote or paraphrased. the only time you don't have to is if you include it in the sentence.

Example for when you don't have to cite in text:

On page 13 Martin says, "blah blah bah bluh bleh blah"   

... otherwise just put the citation in parentheses after the quote/paraphrase like so: (Martin,13)

its d! the final exam asked good luck

eli whitney was an american inventor best known for inventing the cotton gin. this was one of the key inventions of the industrial revolution and shaped the economy of the antebellum south.