The Libraries offer many primary source documents, in a variety of formats.
Many digitized collections can be found on the History databases page.
You can also search the online catalog for primary sources, using words such as: personal narratives, autobiographies, diaries, letters, records, sources, interviews, archives, or archival sources:
Open access web sites are also available, such as the Library of Congress Digital Collections. Many other research libraries have digitized collections that can be found using Google!