How do i update this iOS14.7.1

You can't update to 14.7.1

Update your iPhone, iPad, or iPod touch

• If you have an iPhone 5S or 6/6plus, the highest you can update to is 12.5.6

• If you have an iPhone 6S through 7, you can update to 15.7

• If you have an iPhone 8 or higher, you can update to 16.0.2

Go to Settings > General > Software Update.

Update your iPhone, iPad, or iPod touch using WiFi -

Update your iPhone or iPad - Apple Support

Update using your computer -

Update iOS on iPhone - Apple Support

You could try updating using a computer. This method requires less space on your phone to update.

Update using your computer -

Update iOS on iPhone - Apple Support

Ios 14 is no longer offered. You can update to the current version available for your device, which is ios 15.7.

You can't.

If you decide to update your iPhone 7+, you'll get the latest iOS version for that model (now 15.7).

Regards

Giulio