The Multiple Profiles for Vendors add-on allows a store admin to enable additional users for the Vendor area if vendors, e.g., need a staff member or a business partner to log in to the store and add/update their products or work on the orders. The add-on enables a new user role - "Vendor staff" - which can be given to the staff or business partners of existing vendors to access the products and orders of the vendor.
The vendors themselves decide who they want to invite to the store as vendor staff members. The store administrator does not have to worry about sending invitations or approving new staff users: vendors perform these tasks. The administrator, however, can rename the "Vendor staff" role (the same way as any other role in the store) and can manage the profiles of vendor staff users like any user profile in the store.
The invitation email message used to invite new vendor staff members to the store is a regular X-Cart notification. After activating the add-on, the store administrator should check and adjust this message via the Email notifications section.