Is there a way to let the player draw things on UI in runtime?

Hi guys.
I am research into the game system that lets the players draw things directly on their UI’s
I’ve tried this game:

It’s a game that ask players to classify star data by drawing a marque on the screen.
I’ve seen some UMG designers tutorial and found that most of them are about reading variables inside BP class or CPP classes…

But, Is there a way to reverse it and make the player able to draw things on screen?