A thank you note is a written message expressing gratitude to someone for a gift, favor, or kind gesture. It can be sent in various forms, such as a handwritten card, an email, or a text message. The purpose of a thank you note is to acknowledge the recipient's thoughtfulness and to strengthen personal or professional relationships. Typically, a thank you note includes a brief message of appreciation, specific details about what you are thankful for, and a closing remark. Sending a thank you note is considered a polite and thoughtful gesture, often associated with events like birthdays, weddings, or business meetings.