Credit Note is a document issued to a party stating that you are crediting their Account in your Books of Accounts for the stated reason or vise versa. It is commonly used in case of Sales Returns, Escalation/De-escalation in price etc.
A Credit Note can be entered in voucher or Invoice mode.
You need to enable the feature in F11: Accounting or Inventory features.
To use it in Voucher mode you need to enable the feature in F11 :Accounting Features - Use Debit / Credit Notes.
To make the entry in Invoice mode enable the option F11: Accounting Features - Use invoice mode for Debit Notes.
To go to Credit Note Entry Screen:
Go to Gateway of Tally > Accounting Vouchers
Click on Ctrl+F8: Credit Note on the Button Bar or press Ctrl+F8.
You can toggle between voucher and Invoice mode by clicking Ctrl+V.
Pass an entry for goods sold returned from Customer A:
ALT+R: Recalls the Last narration saved for the first ledger in the voucher, irrespective of the voucher type.
CTRL+R: Recalls the Last narration saved for a specific voucher type, irrespective of the ledger.