Audit trail
TL;DRThe record of what was sent, when, by whom, and what changed since — on every document.
Because sent invoices are frozen and every correction is its own document, the trail is the documents themselves plus the actions on them: who approved the contract, when the invoice went out, every reminder sent, every match made and by whom.
Deleting an invoice cascades through its dependants — credit notes, email threads, matched bank lines, ledgers — so the trail never points at something that no longer exists.
Where it happens in Sonic
Next
See it on your contracts
A walkthrough on the agreements and files you actually bill from — not a slide deck.