You don't need to have the Shazam app installed on your iPhone for this new feature to work. Apple's Music Recognition feature in the iPhone Control Center can now sync with version 15.14 of the Shazam app. It can now also sync across devices using the same Apple ID. This option has begun rolling out to iPhones running on iOS 15. If you have this feature set up, you can press and hold on the Music Recognition button in the Control Center to see the songs you've "Shazam'd" on your phone.