Maybe with reference to this:
About Rapid Security Responses for iOS, iPadOS, and macOS - Apple Support
- Rapid Security Responses are a new type of software release for iPhone, iPad, and Mac. They deliver important security improvements between software updates — for example, improvements to the Safari web browser, the WebKit framework stack, or other critical system libraries. They may also be used to mitigate some security issues more quickly, such as issues that might have been exploited or reported to exist "in the wild."
This support article has instructions about updating an iPhone or iPad wirelessly --> Update your iPhone or iPad - Apple Support Read the article for recommended criteria for being able to use wireless updating.
You can also use Mac and PC computers to update system software --> Update iOS on iPhone - Apple Support
Note that if nothing happens when you try to update, the most recent update had issues and was withdrawn temporarily by Apple. It will presumably be reissued when the problems are handled.