What must all vouchers certified for payment by a Certifying Officer be .?

All vouchers certified for payment by a Certifying Officer must be complete, accurate, and accompanied by appropriate supporting documentation. They should also comply with applicable laws, regulations, and agency policies. Additionally, the Certifying Officer must ensure that the funds are available and that the expenditure is for a legitimate purpose. Lastly, the voucher must be properly signed and dated to validate the certification.