How do i Update the phone

Oxchatom wrote:

How do I Update iPhone 6s

If you are new to iPhones press Settings > General > Software Update. If there are any updates available it will say so. If not it has the latest version already installed.

An iPhone 6s or 6s Plus cannot support iOS 16 or later version, just iOS 15.7.3.

See why in this compatibility chart: