Learn how to use an effective letter of appreciation to show your gratitude for job opportunities, job search referrals, and other kindnesses. I just wanted to thank you for being a great customer and let you know that we value your business.A thankyou letter is a typed or written note that expresses your words of gratitude to somebody for some reason. The message of appreciation should stand alone. Be brief, warm, and sincere. A thankyou letter provides an excellent opportunity to show gratitude for someone's time and effort. They also present you, the sender, in a positive light. I want to congratulate you personally for completing your year with < company name >. It has been a pleasure working with you. We ask that you write a letter expressing your thanks to the donor(s) associated with your particular scholarship.