If an approval is given with an authorization code, be sure to record this information on the sales slip.
An authorization code is required when transferring domains from one registrar to another.
Authorization codes are used for any transaction or entry that has restrictions on which users are entitled to access. For example, only certain individuals will have the authority to approve major expenses, and will probably have an authorization code in the company's records or on a case-by-case basis to complete any approval.
An authorization code is commonly attached to credit card transactions, not only to signal a merchant that the transaction is approved, but also to help identify the transaction in follow-up examinations, such as disputed transactions.