In the rich text editor:
@applebabbles
In a comment:
[applebabbles](https://painted-relics.com/user/applebabbles)
For Names and Avatars:
In the rich text editor:
%applebabbles
In a comment:
[](https://painted-relics.com/user/applebabbles) [applebabbles](https://painted-relics.com/user/applebabbles)