The document number is an 8 or 10 digit alphanumeric number found either on the back of the license or lower right hand corner (depending on the year of your license). It is not the same as the drivers license number. See the FAQ below for a picture example of where to find the document number on a NY license:
https://ttlc.intuit.com/replies/5624473
Re: Where is the document ID number located on a New York state driver's license
My name is : k chan
[PII removed]
[address removed]
@kakeungchan Please return to your post at once and edit out the personal information that you have posted for everyone to see on this public website--including scammers and identity thieves who would love to call you and pretend to be from TurboTax..
Go up to the three little blue dots on the upper right and click them so you can edit and remove your name, date of birth and mailing address.