To effectively craft a thank you note on your invoice that strengthens client relations, consider these tips: personalise the message by using the client’s name, show sincere appreciation for their patronage, recognise details about the services or products provided, and highlight shared achievements. Express your anticipation for future dealings to cement ongoing relationships. It's important to maintain professionalism, keep it concise, and ensure the note is noticeable on the invoice.

Example: “Dear [Client’s Name], we are grateful for your choice in our [service/product]. Your trust is invaluable, and we are eager to work together in the future. Best wishes, [Your Name/Company].”

Tip: Tailor your thank you note to mirror your company’s tone and double-check for accuracy and professionalism. While a thoughtful note can enhance relationships, its effect varies according to customer expectations and industry practices.