In addition there are the following variants:
Copy: Documents the operation to the issuer, with the same data as the original (to be retained by the recipient or recipient). It should be labeled "copy" to distinguish it from the original.
Duplicate: Documenta for receiver operation, in case of loss of the original. The issues the same issuer that issued the original and has the same data as the original. Must be marked "duplicate" to distinguish it from the original permit, if you see the original.
Electronic invoice: is an electronic version of the bill, usually in XML format, which is legally binding and does not need the physical version of the document.
Pro-forma invoice or free form: Documenta commercial bid, indicating the exact form that the bill will after delivery. You have no proof or as book value and is used primarily in international trade for import licenses for the opening of letters of credit or for sending commercial samples because it requires to fulfill the legal obligations of a bill that would result to true. It usually includes the maximum date of validity.
