As each credit customer is invoiced, the details are entered in the sales day book (SDB). The column labelled folio, is the account number of each customer in the subsidiary ledger. The amount net of VAT, the VAT and gross amounts are entered in their own columns. (If the business is not VAT registered, there will only be one amount – the net amount.)
Note that only credit sales are entered into a sales day book. If sales are paid for at the time of delivery, the details would be entered into the cash book instead.
Below shows how credit sales are entered into the sales day book.