Apple announced the move last June, but said in September that it would delay the change to give digital advertisers time to adjust. Some developers are already displaying the notice on a voluntary basis.
Apple has said that it is providing developers with alternative advertising tools ahead of the change. One tool provides a way for advertisers running app installation ads to see how many people installed an app after the ad campaign without divulging information on individual users. Another tool called private-click management gives advertisers a way to measure when a user clicks an ad inside an app and is taken to a web page, but without revealing data about the individual user.
Although the tools are intended to be used by software developers, Apple added information about them to one of its privacy guides for consumers on Wednesday.
Facebook had said in December that it planned to show the pop-up notification because it did not want Apple iPhone users to lose access to its apps.