A voucher is an accounting document representing an internal intent to make a payment to an external entity, such as a vendor or service provider. A voucher is produced usually after receiving a vendor invoice, after the invoice is successfully matched to a purchase order.a payment voucher can be used for a variety of purposes, sometimes taking the place of cash in a transaction, acting as a receipt, or indicating that an invoice has been approved for payment.

Above screenshot represents the voucher invoice in that invoice adding the ledger name, amount, debit/credit generate the voucher and given to the customers.