Go to Company.
Go to Doc Types.
Here you can add as many doc types as you need.
Doc Types have 3 Parts:
Type = Name of the type
Model = Driver, Vehicle, Trailer
Required = Yes, No ( This is used to run required reports )
Company Documents are always set to Default, and Description should be added to each document.
Driver, Vehicle, Trailer documents are always set to Default if no type is required or set.