According to TeachingHistory.org:
"Primary sources are materials directly related to a topic by time or participation. These materials include letters, speeches, diaries, newspaper articles from the time, oral history interviews, documents, photographs, artifacts, or anything else that provides firsthand accounts about a person or event.
Some materials might be considered primary sources for one topic but not for another. For example, a newspaper article about D-Day (which was June 6, 1944) written in June 1944 was likely written by a participant or eyewitness and would be a primary source; an article about D-Day written in June 2001 probably was not written by an eyewitness or participant and would not be a primary source.
Similarly, Lincoln's Gettysburg Address, delivered soon after the 1863 battle, is a primary source for the Civil War, but a speech given on the 100th anniversary of the battle of Gettysburg in 1963 is not a primary source for the Civil War. If, however, the topic was how Americans commemorate the Civil War, then the 100th anniversary speech would be a primary source for that topic. If there's any doubt about whether a source should be listed as primary or secondary, you should explain in your annotated bibliography why you chose to categorize it as you did."
According to TeachingHistory.org"
Secondary sources are works of synthesis and interpretation based upon primary sources and the work of other authors. They may take a variety of forms. The authors of secondary sources develop their interpretations and narratives of events based on primary sources, that is, documents and other evidence created by participants or eyewitnesses. Frequently, they also take advantage of the work of other historians by using other secondary sources. For example, the author of the history textbook which you use in school probably did not use too many primary sources. Instead, textbook authors usually rely on secondary sources written by other historians. Given the wide range of topics covered by a typical textbook, textbook authors could not possibly find and use all the relevant primary sources themselves."