How to update my iPhone 6?

Is your device compatible to update to the new version? See the article(s) below. 

iOS 16 compatible devices

IOS 15 and iPadOS 15 Compatible Devices.  *

iOS 14 and iPadOS 14 Compatible Devices.  *

iOS 13 and iPadOS are compatible with these devices - Apple Support.  *

See instructions in Update your iPhone or iPad - Apple Support

Note that the iPhone 5 cannot be updated beyond iOS 12.5.6.

I want you to upgrade my iPhone 6 so that my mobile app can work and some other app

Please upgrade it

Please can’t update my iPhone 6