Open the app to get to the settings.
Go to the “General” section.
Tap the button that says Software Update.
Give the page a minute or two to load again.
After that, the change will show up.
Click Download and install.
You must agree to the Terms of Service after reading them carefully.
Make sure your iPhone is connected to a power source until the download and installation are done.
You’re using iOS 16.4 beta 2 right now.