Please tap "Remove ads" from application setting screen. Paid fee will be charged, but by charging, the advertisement will be deleted and will not be displayed again. Once you charge it, you do not need to pay the money again. As long as it is the same Apple ID in the future, if you change the model of iPhone for the rest of your life or erase the application, if you press the button "Restore Ads removed" on the setting screen, The ad will be deleted.