User Is This Salesperson

When editing a user with Admin -> System -> Users you can link the user to a salesperson so that when the user creates orders and invoices, they will be the default salesperson for the orders and invoices. Select the user with the User Is This Salesperson field under General -> Additional when editing the user.

You can limit what salesperson-linked users view with the Limit Salesman Access add-on. When the add-on is active and the setting Admin -> Billing -> Company Options -> Block Salespeople From Seeing Orders, Invoices, Customers Other Than Own is on, users will only be able to see customers, orders, and invoices that are assigned to them.