I want to upgrade my iPhone 6s

Please don't make us guess—we're very bad guessers! What laptop model and year?

Are you asking about the iPhone 6S running iOS 15 shown in your equipment line? If so, it is maxed out at iOS 15. See what Settings > General > Software Updates shows for options. If none are shown, your phone cannot be upgraded higher.

The iPhone 6, released by Apple ten years ago, cannot be updated beyond iOS 12.5.7.