In the rich text editor:
@Akichan926
In a comment:
[Akichan926](https://chowlings.com/user/Akichan926)
For Names and Avatars:
In the rich text editor:
%Akichan926
In a comment:
[](https://chowlings.com/user/Akichan926) [Akichan926](https://chowlings.com/user/Akichan926)