Why doesn’t my iPhone give me an IOS 16 update?

What model of phone do you have?

Settings > General > About > Model Name

iPhone 5s, iPhone 6 and iPhone 6 Plus.......can only update to iOS 12.5.7

iPhone 7 can update to iOS 15.7.5

iPhone 8 or higher can update to iOS 16.4.1

If your iPhone is not on IOS 16. First go to settings, general and then software update. If IOS 16 is not there, your iPhone is to old. To get IOS 16, your iPhone must be an iPhone 8 or above.