Take out Pipes Mario Kart Tour?

First you'll need to make sure you are playing one of the tracks where pipes actually show up. Then try to get either a bowser shell or giant mushroom then you can take out the pipe by either firing the bowser shell or running into it if you have the giant mushroom.

Everything is explained in more detail on How to Take Out Pipes on our guide page:

https://www.appgamer.com/mario-kart-tour/strategy-guide/take-out-3-pipes-challenge