push notification on third party apps

Every time i open a third party app on my iphone 7 ( weather channel, instagram, facebook) my phone asks me "app would like to send you notifications". I mean every time even if I never signed out of the app, i go to the home screen not closing the app and then go back to the app, it does it all over again.. This is obnoxious. How do i stop this window from popping up?