Specify whether IDs will be automatically assigned to all documents in the Site Collection. Additionally, you can specify ...

            Specify whether IDs will be automatically assigned to all documents in the Site Collection.
            Additionally, you can specify a set of 4-12 characters that will be used at the beginning of all IDs assigned for documents in this Site Collection, to help ensure that items in different Site Collections will never get the same ID.
            Note: A timer job will be scheduled to assign IDs to documents already in the Site Collection.