Hi @Vindya Wijesinghe 

a buyer is a person who works in the purchase department. He is respnsible for acquiring parts for a good price, on right time, right quantity and qualitity.

A coordinator is a expert between the sales department and the customer. He is responsible for the whole organisation and coordinates the shipment, production, financial etc. Furthermore respnsible for monitoring, complaints, inventories etc. Their main focus is on demand management.

So far from my site. :-)

I would deem Buyer a required field in the application to identify the individual responsible for a given purchase order.  This field is useful for sorting requisitions to be actioned, orders to be tracked, and  main contact for the supplier within our organization.

I would say that Coordinator is optional in the context of an actual person.  We have a schema where Coordinator is always * because we use the same setup for all orders at all sites without splitting them by a Coordinator.  We in fact have removed the coordinator field from the view of users on all profiles.  We set every user with a default coordinator of * so they are unaware of the function being driven in the background.

The Coordinator however is built into the logic that drives the automatic numbering of many order types within IFS, so while in our view it is not a designated function, it is still a required field by IFS.  This is defined on the Coordinator Group.  The Coordinator Group ID becomes the prefix for Customer Orders and the prefix for some other orders can be defined here also.