PDF/A is a new(ish) file format. It’s a long-term archival version of the classic PDF format we all know and love. Basically, it’s the same as regular old PDF, but it’s guaranteed to look exactly the same years from now when you open it on your holographic iPhone. It should be super easy to implement since the scanning software we currently use, Adobe Acrobat Pro, already has settings for scanning/converting to PDF/A.
White paper from the PDF/A Competence Center which explains the standard in easy-to-understand language.
Report from Ohio State University Library which discusses different options for converting documents using Microsoft Word and Adobe Acrobat Pro.
Great Adobe Acrobat Pro tutorial which explains exactly which features are and aren't PDF/A compliant. (Note: The narrator has a very soothing accent.)
Uses email to verify attached PDF/A documents.