When do I use receivable debit and credit memos?

Debit and credit memos are accounting documents used to adjust the receivable balances of your customers. Debit memos (like invoices) are used to indicate when your customer owes you money. Credit memos are the opposite. They are used to indicate when you owe money to your customer. For example, let's say a customer sends you a check for $1,000 but they only owe you $850. This would leave you owing your customer $150, an amount which would be contained in a credit memo.