Document types provide a specific classification for documents and images. Since you must assign document fields to document types, you should create your document fields before you create the document types. For information on setting up document fields, go to 
NextGen Healthcare Success Community and download the latest 
User guide for NextGen Document Manangement and see 
Set Up Document Fields. 
  
Note: NextGen Healthcare recommends that each document type has one Person Number key field associated with it to serve as a unique identifier. Therefore, to associate a person number to each document type, in the Document Type Information window at File Maintenance, select the Potential Order Result  check box and mark the Person Nbr field as Required.