INDENT: Suppose I require a certain items of desired quantity and specifications from a supplier. The written document asking for supply of goods is said to be Indent.
INVOICE: The Supplier in return along with the goods/items as indented and a written document of that goods/items deliver to the Indenter. The receipt of that goods along with the acknowledgement of the indenter in one copy is an invoice.
BILL: The Customer copy(Indenter's Copy) of the goods received along with the certification of the head/chief that the goods found to be of approved quality and quantity and have been entered in the Stock Register Folio for further action is said to be Bill.
VOUCHER: It is the proof of payment either in Cash or Cheque/Draft to the Supplier based upon the billed amount.In the aforesaid Bill, the necessary entry that "Passed for payment vide Cheque No...... dated......" is to be recorded.