Yes. Each VDM partner that is granted an Operator role on an advertiser's account can technically create new vouchers for any app under that account. A VDM partner can only access vouchers that they created. Such vouchers are not visible to any other VDM partner, however, they are visible to the advertiser.
A VDM partner receives an Operator role on an advertiser's account once he onboards a new advertiser to TROPHiT or requests Operator access from an existing advertiser.