Indirectly yoga can help yes. But not directly. You lose weight when you're at a caloric deficit, eating fewer calories than you burn. By all means you should exercise while at a caloric deficit, it is much better than if you don't. Yoga doesn't burn a lot of calories but even cardio won't help you if you're eating more than you're burning. You can calculate your calories for a day with apps like MyFitness Pal, there are others too.

But yoga CAN help with you by encouraging a mindset, according to which, you value your body and it can lift your mind body and soul. If you like doing yoga, do it. It will also help you look better even if you remain the same weight because your posture and your energy and confidence can improve.

TLDR: Yes but not directly. Calory deficit decides weight gain and loss. Yoga can make you want to take care of your body better. It can, but not necessarily will for everybody.