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