The source documents are the paper (or electronic) record of all the businesses transactions. These documents are then recorded and summarised as part of the bookkeeping and accounting process.
Examples of source documents are: sales order, purchase order, invoice, credit note, goods received note, bill of lading.
It is vital that a business keeps copies of all its source documents as evidence for audit and/or the inland revenue.
Not every business produces or needs to produce all the different types of source document. For instance, a service industry is unlikely to have a “bill of lading” as there is no physical product to ship.