What is a letter from Tik Tok?

Tik Tok's "A Letter" is an activity topic, and it is a WeChat activity: edit what you want to say or hope to someone through the official WeChat account or applet such as "A Letter DY", and the official WeChat account or applet will send what you want to say to your reserved number, which can be a specific time or a specific topic.

The recent rise is to send New Year greetings to friends or secret admirers without revealing your information to each other.