But I have seen many apps, such as video watching apps or exam apps that require confidentiality. They do not restrict the system's screenshot function, and the content they screenshot on a certain page of the app is a white/black screen

Our environment does not allow other phones to bring in, but the current requirement is to prohibit the use of iPhone's built-in screenshot to capture information on the current page. Only white screens or custom pages can be captured (I have seen this solution on other apps), but I don't know how to implement it. Do you have a good solution