Write a quotation you know from memory and attribute it to the person by name when writing an in-class essay. You will most likely not be expected to write a formal bibliographical citation for an in-class essay where you do not have citation sources as your disposal. It is, however, important to know the exact words of the quotation and to provide the speaker's name. For example, you could write, "As Franklin D. Roosevelt said in his 1933 inauguration speech, 'The only thing we have to fear is fear itself.'" Failing to cite FDR as the speaker would be unacceptable.
Do not use formal citations when writing news articles for the college newspaper or a journalism class. It is important to attribute quotes to people who you quote in your news story, but a formal bibliographical citation is not necessary. For example, it would be acceptable to write "Greentown police chief, John Smith, said the fire was "not suspicious in any way, shape, or form." However, it would be unacceptable to use the quote and fail to mention the police chief as the speaker.
Never cite quotations of fictional characters in a work of original fiction. For example, if you have been assigned to write a short story for your creative writing class you should not use a formal citation when quoting a fictional character that you yourself invented.
Do not use a formal citation when you place rhetorical phrases or questions in quotation marks within a piece of writing. For example, if you write, "The state of the world really has people wondering- 'What's the point?'" a citation is not necessary.