I scan receipts, invoices, manuals, taxes, etc - all documents that enter my home. Paper shredder is right next to the desk. Docs are queued on desk inbox, on weekends I scan them and then immediately shred. I use the Fujitsu ix1400 scanner and it's included ScanSnap software. All scans are in PDF format and automatically sync'd to a local Synology NAS and then to (encrypted) cloud. I have 20 years' worth of documents using this approach and can get to any of them quickly from anywhere on the planet via mobile app.
I do not link them directly to YNAB in any way, but my folder structure allows me to find them easily if needed.