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