debit note and credit note in gst

https://keydifferences.com/difference-between-debit-note-and-credit-note.H T M L


https://cleartax.in/s/debit-note-credit-note-and-and-how-to-revise-gst-invoices

Who will be the issue debit note and credit note

Any one will be issue the both as per their transactions... But, Generally


No more specified person issued the above said Credit Note and Debit Note... These are issued based on the transaction...

Sales Return (Credit Note) :
A Supplier (seller) will be receiving his supplies goods from Customers in any problems then He is received the goods in a document it's name of Sales Return or Credit Note. Also credit note prepared some of other credits.... 
Purchase Return (Debit Note) :
A Buyer will be returned the goods to his Supplier for any problems he can issued a document it's name of Purchase Return or Debit Note. Also Debit Note Prepared some of the Other Debits... 


Note :
Both transactions not only as per above way some times it will preparable buy opposite party's for any other manner...

See this video to understand credit note and debit note in detail https://youtu.be/kkjIsrORrHM