The key is to create a snapshot of the current version each time it is sent, not just store the final version. Each modification should record: which party proposed it, which fields were changed (items, quantity, unit price, delivery date, payment terms), the timing of the change, and the other party's response. If the customer's reply can be directly linked to that version of the quotation, later you can trace back 'why did we reduce the unit price by 5% in the third version' with evidence. This is critical not only for AI learning, but also for staff handover, customer complaints, and contract disputes. Centralizing quotations and POs in one system, creating a PDF snapshot each time you send, and being able to compare any two versions using a diff view is the most basic approach to making this process meaningful.