How to update my iPhone to the latest iOS version ?

To update to the most recent, compatibile version of iOS, please 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. 

You can only update an iPhone XR to iOS 17. Go to Settings/General/Software Update and you should see instructions.

Why are you update your storage