<prompt> Translate the following text to EnglishKwa mfano, idhini hizo zinaweza kuthibitishwa na maagizo ya ununuzi yaliyotiwa sahihi na ofisa aliyeidhinishwa au maagizo ya kusafiri na voucher zilizotiwa sahihi na wasimamizi.  <response>: For example, such approvals could be evidenced by purchase orders signed by an authorized official or travel orders and vouchers signed by supervisors. 