Hi ,As far a my understanding .Debit note is a document , the buyer gives that to the seller in case of any damage /defects in delivered products.Buyer will return the product the debit note ,once the seller accepts it , they create a credit note and reverse /refund the amount. Check below screen shots for more understanding.

Stock moves details will get from inventory.

When you are creating a Credit Note/Debit Note, it will reverse the actual invoice/bill.

You can check Odoo's documentation for this.

https://www.odoo.com/documentation/16.0/applications/finance/accounting/receivables/customer_invoices/credit_notes.html