A debit note is a document sent by a buyer to a seller, or in other words, a purchaser to a vendor while returning goods received on credit. This notifies that a debit has been made to their accounts.
A debit note is issued for the value of the goods returned. In some cases, sellers are seen sending debit notes which should be treated as just another invoice.
How to make debit note in ERPNext
The user can make a debit note against the purchase invoice or they can directly make debit note from the purchase invoice without reference Goto module Accounts > Purchase Invoice > New > Manually enabled Is Return checkbox
Note: For debit note set the negative quantity while adding the item
Debit note with payment entry in ERPNext