How do you tag a user so that they get notified?

I searched this forum, vbulletin help, and bbcode help, and I couldn't figure out how to do this.

I want to be able to tag someone, like @RickyTimothy , and have them get notified about it in the post, as well as have it be a clickable link.

What is the correct way to do this?

I'm no computer expert but I don't think you can do that. But I may be wrong. I'm sure someone else will come along who knows more. Worse comes to worse you can shoot an email the admin Ivan about this. His handle is Gugi.

I doubt this can be done. I would not want someone to have the ability to make me receive unwanted emails.
A bad actor could have everyone on the forum receive their spam.

You can do this for yourself on threads you choose. This is the Thread tools. You can subscribe to a thread. It is right above the first post.