A document number is a unique combination of numbers and letters used to identify a specific document, regardless of its type. It is often assigned contextually and is usually unique. The document number is different from your drivers license number or ID number, which identifies you as an individual. The document number is attached to a specific license or ID card, and when you renew it, the number changes because you get a new card from the DMV. The document number can be found in various places depending on what type of ID it is and when it was issued. For example, in New York, the document number is an 8 or 10-character combination of numbers and letters on your license, permit, or non-driver ID, and it is printed on the lower right corner of your DMV photo document or on the back for documents issued after January 29, 2014. The document number is used to identify your document, and each document issued has a unique number. You can use the document number from your most recently issued license, ID, or permit for MyDMV or to register to vote.