Return Process in vendor and customer systems

Hi experts,

here is the scenario:

A customer returns a prdouct he received from vendor on account of quality defects.

What is the standard process followed by industry for this return scenario both in customer and vendor R/3 systems?

Does customer sends any ASN or IDOC or any other communication to the Vendor along with the returned products?

If the vendor receives any communication in form of IDOC or ASN then how does he comes to know that the customer has sent a return delivery?