What key detail must be present in customer identification on invoices?

The inclusion of the customer's full name and contact information on invoices is vital for several reasons. It ensures that there is a clear record of the transaction, linking the services provided directly to the customer. This detail not only facilitates effective communication in case there are issues or questions regarding the invoice, but it also aids in compliance with legal and regulatory requirements. In many jurisdictions, having accurate customer information is crucial for identification purposes, especially in industries that require transparency and accountability, such as the travel sector.

Maintaining complete and accurate customer information can also enhance customer service, as it allows travel agents to quickly reference prior interactions or preferences, ultimately leading to better service. While other details like birthdates, payment methods, or travel preferences may be relevant in specific contexts, they do not serve the foundational role of identification in transactional records as the full name and contact information do.