Invoices function as an important purpose for both, the business directing the invoice and the client accepting it. For small companies, an invoice supports expedite the expense by providing customers a statement of the payment that is unpaid. Not just that, a bill also aids you to track your company’s sales and income and retain your books of accounts updated. With VAT in Oman, the invoice issuance grabbed more importance. This is because the VAT law orders all the industries registered for VAT to offer an invoice on making a taxable supply.