vouch·er / ˈvouchər/ • n. a small printed piece of paper that entitles the holder to a discount or that may be exchanged for goods or services. ∎  a receipt.

VOUCHER

A receipt or release which provides evidence of payment or other discharge of a debt, often for purposes of reimbursement, or attests to the accuracy of the accounts.

Government or corporate employees usually submit vouchers to their employers to recover living expenses they have paid while on business trips.