I have a query, I have a credit note from my supplier, but this credit is not associated with a specific product, it is just a discount for marketing support or some other campaign, how could I handle this or what account should I create for this type of operations

Also when I have processed an invoice and after it is issued I want to apply a discount to the client for any reason that is not associated with a product, such as how can I register a credit note without affecting my inventory of products