How can I install iOS 15 and above as a beta profile on iPhone 6?

beta profile ios 15Swipe down and tap Install Profile next to the iOS 15.4 beta or iPadOS 15.4 beta; Tap Allow to download the profile, hit Close; Head toFind the iOS 15 profile and make sure that you enable the download. Head to Settings > General > Software update and then you should see the iOS 15 beta appear. Press the Download and Install button.