Will Siri be able to control apps in IOS 27?

We can’t verify that Siri will be able to control apps in iOS 27, because that version is far in the future and Apple hasn’t announced it.

What we can say is that Siri already has some app-control abilities on supported devices, and Apple has been expanding those capabilities through Apple Intelligence, on-screen awareness, and app integrations. So it’s reasonable to expect Siri to keep getting better at controlling apps over time, but the exact feature set in any future iOS release is unknown until Apple announces it.

If you mean today’s Siri, it can already perform some app-related actions, but how much it can do depends on the app, device, language, and iOS version.