The upcoming version of iOS will be installable on your iPhone if it is at least the iPhone 8 or newer.
Unfortunately, this also means that the 7 is out. The 6s had an extremely long support and can now retire. Nevertheless, security updates should still come from Apple for the then older systems, but there is no publicly communicated time frame for this.
With iOS 16, Apple will introduce a personalizable lock screen and also improve photo sharing between family members. For smart home users, it is interesting that Apple will also support the Matter communication standard with iOS 16 and a revised Home app. This will allow even more devices to be integrated into the Apple Smart Home – if more devices with this standard are launched on the market.