In the rich text editor:
@Blair
In a comment:
[Blair](https://chowlings.com/user/Blair)
For Names and Avatars:
In the rich text editor:
%Blair
In a comment:
[![Blair's Avatar](https://chowlings.com/images/avatars/8.png?v=1644063330)](https://chowlings.com/user/Blair) [Blair](https://chowlings.com/user/Blair)