Each company has its own rules when creating document numbers for different documents. The default setting in SAP Business One is to assign a separate numbering series for each document type. If users want to change the document number in the default setting, they can go to Administration and choose Document Numbering.
Actually, SAP Business One has another way to record document numbers; you can have more than one document type per series. Before posting any document or transaction, go to Administration > System Initialization > Company Details > Basic Initialization tab and click “ Permit More than One document Type per Series.” Please note that selection of this checkbox is irreversible.
After you click the box, the menu will change a little. You may find Document Numbering under Administration.
Here you can add or edit the series and set a series as default.
If you are interested in learning more about how to define multiple bar codes for each unit of measure and each item, please visit Bar Codes in SAP Business One.