Changing Document Names 
If the names defined in the application do not correspond to your company’s terminology, you can assign your own names to documents.
You can change document names even if documents have already been entered in the system.
Note
Changing the menu name of a document is possible only if the Permit More than One Document Type per Series checkbox on the Basic Initialization tab of the Company Details window is not selected.
Note
You cannot change the names of the master data.
Procedure
From the SAP Business One Main Menu, choose
Administration 
System Initialization Document Numbering 
.Enter the new name in the Change Menu Names column of the relevant row.
To save your entry, choose Update.
Choose OK.
Result
The new name appears in the SAP Business One Main Menu and in the title bar of documents of this type.