There is a great resource offered by the Library of Congress that allows anyone – no account or fee required – to access primary sources scanned by the Library. What’s great about these resources is that they are available on the web in PDF formats. Students navigate to the website, find the source they want, and on an iPad, can use the “open in” option to import into a variety of applications. I suggest using Notability.
Once the students have the document in their Notability app, they can edit the primary source. Not only is this a great site for teaching students about primary sources, but it is loaded with resources that are accessible directly on the iPad. Also, each primary source set comes with a teacher’s guide in PDF form. This allows teachers to open these guides directly on their iPad in iBooks, Google Drive, etc.
Below is a short video on how you can get started using the Library of Congress resources with the iPad.