Which of the following must be included on a simplified invoice?

A simplified invoice serves the purpose of streamlining the invoicing process while still providing necessary information for both compliance and clarity. The inclusion of a description of goods or services is essential because it provides the recipient with a clear understanding of what they are being charged for. This clarity helps in verifying the transaction and ensures that both parties are aligned on the nature of the services or goods exchanged.

When a simplified invoice is used, the requirement often allows for fewer details compared to a standard invoice, but the description of the goods or services remains a fundamental requirement, as it directly relates to the transparency of the transaction. Including a description helps in addressing any potential disputes regarding what has been provided or purchased.

In contrast, the other options, while useful in many contexts, are not mandatory on simplified invoices. For instance, the supplier's phone number may facilitate communication but is not essential to meet invoicing requirements. Similarly, the date of delivery, while important for tracking and disputes, may not be necessary in every simplified invoice context. Lastly, a tax identification number of the customer may not be required on all types of simplified invoices, especially when less detailed documentation is permissible under tax regulations. Thus, it is the description of goods or services that is crucial for clarity and compliance