Validity of documents has the following types: A: in terms of the validity that is on two species: A- reversible credit that the buyer’s buyer’s head is also revoked and is itself two types: (1) transferable 2 of each of their high double credits on two species: (1) non-departable 2-b-credited credit, which is exclusively the bank’s valid authority to the terms which are executed in accordance with the price. This type of credit is based on two types: (1) transferable 2-in transferable, as well as each of the credits taught on two types: (1) non-departmental 2 credits of documents may be two or more steps. This means that it can be received in two stages or several steps before carrying the goods. In the opening leaves, the validity of the conditions of this type of documents is provided with a red compound on valid openings, so it is called red bet credit. Second: In terms of length, the tariff is also based on two species: A-crediting visual documents is paid for by the interest of the bank. (b) The validity of long-term documents in this form of credit is not immediately paid by the beneficiary to the Labour Bank, but will be paid according to the terms of credit after the anticipated deadline called sis. Webigence is that the credit banker commits the payment of the transaction to the beneficiary by obtaining the necessary guarantee or collateral of the buyer, and therefore the seller is not concerned about the receipt of his claims.