When is the Communication Email under Supplier Purchasing Site Tab used for sending PO PDF?

Summary:

When is the Communication Email under Supplier Purchasing Site Tab used for sending PO PDF? Is PO always sent out to this email or is there a hierarchy? Contact first, etc.

Content (required):

When is the Communication Email under Supplier Purchasing Site Tab used for sending PO PDF? Is PO always sent out to this email or is there a hierarchy? Contact first, etc.

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