Please refer to the steps below on how to report a player.
Go to your profile.
Then, go to “Match History” and tap the thumbnail of the player that you want to report, then tap on Report.
Next, choose your reason why you want to report the player and fill out the necessary details, then hit on the “Submit” button.
Note: You can only report human players. If the report button does not show up when you tap your opponent’s profile in your Match History, that means you faced a bot and cannot report it.