Why my I phone 7 no update

• If you have an iPhone 7, you can update to 15.8.2. Your phone doesn't have the hardware needed to run anything higher.

Go to Settings > General > Software Update.

This link will show you how to update your iPhone, iPad, or iPod touch using WiFi -

Update your iPhone or iPad - Apple Support

This link will show you how to update using your computer -

Update iOS on iPhone - Apple Support