Every user must be assigned to at least one branch to be able to create any document. If you are not assigned to any branch, you can access existing documents as read-only.
From SAP Business One Main Menu, choose
In the Users — Setup window, find the user you need to assign or specify a new user code.
Choose the button of the Branch Assignment field.
In the Branch Assignment window, in the Assigned column, select required branches.
Choose the Update and OK pushbuttons and return to the Users - Setup window.
Choose the Update pushbutton.
You can create documents only for branches to which you are assigned. If you create documents based on other documents, you must also be assigned to the branches to which the latter documents belong.
When creating documents, you can use only master data that share branches with you.