Both. Yoga and Exercise have different benefits. It depends on what you want for your body. If you’re looking to lose weight quickly and build up muscle mass then you should strictly workout.
If you want to build strength, improve your focus, and have more mental clarity then you should pick yoga. I think the best option would be to alternate between the two so that you can get the best of both worlds. To help with the weight loss you can also use a supplement like Resurge. Resurge combined with yoga and exercise will help you achieve your dream body.