How to update my iPhone 7

First iOS 16.1 won't be released until Monday, October 24, 2022 but you will not be able to update to it. The iPhone 7 doesn't have the hardware to run iOS 16, the highest you can go is iOS 15.7.

Not possible. The highest iOS version that you can install on your iPhone 7 is iOS version 15.7.

Axel F.