Add exposed filter for user roles In Ubercart, the uc_order view (admin/structure/views/view/uc_orders) uses exposed filters for status and order ID. 

I can add another filter, for example username, email and so on by clicking on Add filter criteria and selecting the criteria (user:username, user:email). 

I need to add a filter to filter orders by the roles assigned to customers. There is no option such as user:roles in the filter criteria list to select. 

How can I achieve this?
By configuring the Access: section on the Page settings, we can manage Page: Access restrictions.

Choose the Roles  and assign the required user role.