Endorsement: Sign on the back of a bill or document. The express right of a bill or document is transferred from the endorser to the endorsee.

Qualified endorsement. Some qualified endorsements stipulate that a bill of exchange is only delivered once, and the transferee can only use the bill himself without the right to transfer it again. If the endorser signs the back of the bill, indicating "only ××× (name of the endorsee)" or "payment to ××× (name of the endorsee) is not transferable". Others give some additional conditions, "when xxx, pay xxx (endorser's name)." When the conditions are met, the endorsement is established. Some endorsers declare that the holder can only deposit the bill in the bank and cannot use it for other purposes.

In a narrow sense, negotiable instruments only refer to the negotiable securities for the purpose of paying money, that is, the negotiable securities issued by the drawer according to the negotiable instruments law and unconditionally paid by himself or others to the payee or holder. In China, bills are bills of exchange, checks and promissory notes.

Cash checks, bills of exchange and other bills cannot be transferred by endorsement. Transferable checks, promissory notes and acceptance bills can be transferred.