During a game, click on the golf ball in the bottom right corner, you should see a pop up with two sections. The bottom section is for setting spin and the top section is for ball effects. In the ball effects section you need to look for the no ball effect 🚫 symbol (you might have to scroll down), click on that, then you should have no ball effect.
You can buy balls that have a vapour trail, but you cannot shut that off. Check the ball name and the picture to make sure you know what you are buying, the vapour balls are more expensive.