Ios 16 not installing

Check Settings>General>iPhone Storage. Let the list of apps load. Swipe down to find the downloaded iOS software. Tap on it. Delete it in the next screen.

Close the settings app completely. Restart your phone and go to Settings>General>Software Update and try again.

Try a forced restart and then see if the software will install.

Force restart iPhone - Apple Support

You must be connected to WiFi (not a hotspot) and you must have at least 50% battery charge (preferably have it plugged in). Make sure you do not have low power mode turned on.

Is it possible to delete the iOS software like I described in my first post? If you can delete it, force restart the phone and try again.

Also, turn off automatic updates.

This may prove to be of some help. It can’t hurt to take a look.

Updating iOS: common issues and solutions - Apple Community

If you are connected to WiFi, plugged in to charge and are not on low power mode, I would try restarting the phone again and see if it works then.

It can take 15, or 20 minutes or more to prepare. How long has it been?

I’m sorry, but I don’t know what else to try at this point other than to contact Apple for help. You can use this link to get help from Apple.

Apple Support

What happens when you try?