The following documents are important for overall transactional understanding.

1. Order: this reserves Stock but has no accounting effect, this is accompanied by an order number at the point you want to start transacting, this is an indicator that a purchase has been initiated but a payment has not been made.
2. Invoice: This is a Liability Document that holds the store liable to deliver/hand over goods that have been purchased because an invoice is generated upon payment allocation and payment has been made. This has an accounting effect.
3. Shipment: this is the process of transporting/delivering goods to the consumer/customer based on service types offered by the store(some do not deliver), this is per the Order and Invoice issued after payment completion(allocation
   
4. completed and payment terms are met).
5. Payment: this refers to a transaction that is against the order, and that is used to create an invoice. 
6. Allocation: Has accounting implications and is linked to payment, this permits an invoice to be generated.