In the rich text editor:
@Lilystar321
In a comment:
[Lilystar321](https://chowlings.com/user/Lilystar321)
For Names and Avatars:
In the rich text editor:
%Lilystar321
In a comment:
[![Lilystar321's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Lilystar321) [Lilystar321](https://chowlings.com/user/Lilystar321)