There are many kinds of primary sources. Primary documents vary by discipline, and sometimes by the reader's perspective. Not sure what kind of document you are looking for? Consider these:
Primary sources provide firsthand evidence of historical events. These include letters, diaries, photographs, speeches, and other documents. Many of these are unpublished, one-of-a-kind items.
A growing number of Primary Sources are available on the web, thanks to digitization projects by libraries, universities, and other agencies.
The term Primary Sources is occasionally used to mean "empirical research" or "original case studies." If you're unsure about the Primary Sources you need for class, please consult with your instructor.