The line below the WeChat name is usually a personalized signature or personal introduction, which is used to show the user's personality, attitude or briefly introduce himself. This line of text exists for the following reasons:

1. Display of personal characteristics: Personalized signatures can show others your unique personality, interests, hobbies, or values. By adding a line below your WeChat name, you can convey your characteristics and personality to others through short sentences or words.

2. Self-introduction: Add a line below your WeChat name to briefly introduce yourself, such as occupation, location, personal declaration, etc. This way others can better understand your background and characteristics when they see your name.

3. Status expression: Sometimes, people will express their status or mood in a line of words below their WeChat name. This could be an inspirational quote, a humorous quote, or a description of your current life situation. In this way, you can share your mood and feelings at the moment with others.

The advantage of adding a personalized signature or personal introduction is that it can make your WeChat name richer and more interesting. Not only does it attract others' attention, it also helps them get to know you better. At the same time, it is also a way to show your personality and express yourself. Therefore, many people like to add a line of text under their WeChat name to increase their personalized display.