See "Update your device using iTunes" here. Be certain you have iTunes 12.6 or later.
Update the iOS software on your iPhone, iPad, or iPod touch - Apple Support
See "Update your device using iTunes" here. Be certain you have iTunes 12.6 or later.
Update the iOS software on your iPhone, iPad, or iPod touch - Apple Support
See "Update your device using iTunes" here. Be certain you have iTunes 12.6 or later.
Update the iOS software on your iPhone, iPad, or iPod touch - Apple Support
What did you do? My iphone 7 update was stucked to "Update Requested"
Software update stuck on "update requested"