Why Boruto Has 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.

Why does Boruto have Jougan in one eye?

The Jougan may be a result of Boruto's genetics. If so, it is possible that Boruto has inherited other powers through his Otsutsuki genealogy. Boruto may be the only one who poses a real threat to the Otsutsuki clan.

Is Jougan stronger than rinnegan?

2 CAN RIVAL: Jougan

While the extent of its abilities hasn't been revealed to us, we do know that it'll be strong enough to rival the Otsutsuki power, which makes it comparable to the Rinnegan.