What is a credit note?
A credit note is a note that says part or all of a bill is canceled, usually because something was returned or there was a mistake. It records the date it was issued and often points back to the invoice date so everyone knows when the change happened.
For example, if John Hotdogs burns one of the hotdogs he sold to Clara, he can send a credit note dated March 4 that links to their March 3 invoice and removes the $5 for that burned hotdog. Those dates make it easy for Clara to see when the price changed and for John to keep tidy records.