Answer
The mechanics vary by document type. Spool file capture typically works through an output queue monitor or a writer exit program that intercepts print output as it is created, then extracts index values either from fixed positions on the printed page or, more reliably, from structured data passed alongside the spool file rather than parsed from the printed layout. Scanned paper and inbound email attachments need OCR or manual indexing instead, and accuracy on those inputs depends heavily on document quality and how consistent the source formatting is.
Buyers should test this against documents that are not clean, invoices from different vendors with different layouts, a spool file with an unusual form type, a scanned document with a coffee stain, because vendor demos default to their best-case sample. It is also worth asking what happens when index extraction fails: does the document land in an exception queue for manual review, or does it silently fail to index, which quietly breaks searchability months later when someone needs to find it.
Approval routing on top of captured documents should reflect how the business actually signs off today, tying into existing approval hierarchies and dollar thresholds rather than forcing a generic one-size-fits-all workflow that staff will route around.