uplatnica

1. payment slip
   Popunite uplatnicu i platite taksu u pošti. — Fill in the payment slip and pay the fee at the post office.
   Na šalteru su mi tražili uplatnicu za administrativnu taksu. — At the counter they asked me for the payment slip for the administrative fee.

The official name of the form is nalog za uplatu; its fields include uplatilac, svrha uplate, primalac, šifra plaćanja, račun primaoca and poziv na broj.