I'll make this a bit long-winded for anyone who doesn't know how courtroom artists work in the US.

Most of the time - cameras and video capture is banned. I assume it's only in very rare situations (in certain states) that artists are allowed to use a mobile device to create. I don't know what the artist used. But whatever crayon-like thing she used or or ink, pencil, or whatever any artist uses - the key thing is that it allows them to create their drawing/illustration at lightning speed.

And that's the total extent of what I know about this.