How to remove PDF warning on iPad?

You are seeing an ad from the game you were playing. The purpose of the ad is unknown, but likely links to another app they want you to download and the developer is paid to show you that ad. The icon in the lower left corner belongs to AppChoices that participating advertising companies use for displaying those ads.

You have a couple of choices:

• Contact the Developer of the game you were playing that displayed that ad to you.
• Quit playing the game that displays ads you do not want.
• Some games offer in-app purchases to eliminate ads. It is you choice on whether you want to pay the developer so they do not display ads to you.

Presumably this game was "free" to download from the App Store.

App Developers don't work for nothing. If you don't "pay" for the game, their work is monetised through other means - typically by advertising or by selling your data - or access to you.

Is there a small in-App purchase that suppresses advertising? If yes, this may be the solution. Otherwise, you might be best advised to simply delete the game from your device.

When do you see this message? Perhaps you see this when accessing a particular website - or when following some other activity with your iPad?