Primary sources differ from discipline to discipline. In general, they contain or illustrate original or first-hand information, created at the time of the event, or later by someone who witnessed or experienced the event. Examples of primary sources include: Letters, diaries, journals, memoirs, personal narratives, interviews, lab notes, conference proceedings, etc. In English studies, novels and poems are primary sources. In music studies, lyrics and songs can be primary sources too.
Below is an example of a primary source about Taylor Swift: a diary entry she wrote in 2009.
September 18, 2009 diary entry by Taylor Swift. Image from New York Times.