When Does Boruto's Jougan Activate?

The Jōgan depicted in the anime. When first used during his time in the Academy, Boruto did not appear to have the ability to activate it on command; instead, the eye would involuntarily activate when Boruto focused his attention on a particular person or object.

What episode does Boruto use Jougan?

Episode 15 was the finale of the Nue arc(I think). Now in this episode the jougan didn't appear, but Toneri appeared for the first time and he revealed that the Boruto's eye is called Jougan.

How did Boruto activate Jougan?

Boruto inherited Jougan because of his bloodline from Hinata and Naruto, not because Toneri or someone mysteriously gave him the eye. What about the destiny which Toneri mentioned for Boruto? It means Boruto is destined to help the world and prevent it falling to the darkness.