How to install iOS 17 update?

Assuming you have a compatible device, see: Update your iPhone, iPad, or iPod touch - Apple Support

And: If your iPhone, iPad, or iPod touch won't update - Apple Support

If the above Apple articles do not help, please post back with relevant information. 

I can’t update my iPhone to iOS 16 version

Malpetthawa1975 wrote:

I can’t update my iPhone to iOS 16 version

Why not?

ios 16 requires an iPhone 8 or newer.