Your appreciation to the donor for their generosity. Learn how to write an employee appreciation letter with these templates and examples.Download the template for free (PDF or Word). I would like to express my sincere and heartfelt thanks for the wonderful and professional treatment received therein. Below you will find sample appreciation letters to send or email an individual or individuals who have helped you at work. Read on for five thank-you letter examples and templates, and a little more on gratitude. This manual is designed to assist hiring managers with appropriate hiring processes and Human Resources practices.