An effective invoice email should include the following key elements: - Invoice Number: A unique identifier for tracking and reference. - Date of Issue: The date when the invoice was generated. - Due Date: The deadline by which payment should be made. - Itemized List of Services/Products: A detailed description of the products or services provided, including quantities and unit prices. - Total Amount Due: The total amount the customer needs to pay. - Payment Instructions: Information on how the payment can be made, such as bank details or online payment links. - Contact Information: Contact details in case the customer has any questions or issues regarding the invoice.