Sight: Generally used in letters of credit and money orders (PAYAABLE AT SIGHT)

Issue: Generally used to issue bills of lading ( ISSUEING B/L (Issuance of bill of lading)

Signature: For example, if you have a bill in hand and want to collect payment from the payer, the payee will pay immediately after seeing the bill if it is on sight. There is no signature. If it is postdated, the payer's signature, date, or some explanation must be added to the bill: XX days from the date of seeing the bill, etc.