A document number is a unique identifier assigned to a document, regardless of its type, to help identify and find it. It is often used to verify identity in various settings, such as a passport, drivers license, or birth certificate. The document number is usually a combination of numbers and letters and is unique to each document issued. It can be found in different locations depending on the type of document, such as the upper right-hand corner of a passport or on the front near the top of a drivers license or non-driver ID. In the context of customer verification, the document number refers to the identification or proof of identity document number, such as a passport or national ID number. The document ID number, on the other hand, is a unique code assigned to a document to help identify it and is used to offer better and faster support.