can't back an iphone to my hp laptop

Hi

It may help to follow the steps here:

If your iTunes backup couldn't be completed or you can't restore from a backup - Apple Support

Note that, for iTunes to be able to connect with a device running iOS 10 or newer, your computer must be running iTunes version 12.5.1 or newer:

Get the latest version of iTunes - Apple Support

If you continue to experience issues, you may wish to consider backing up your iPhone and iPad via iCloud instead:

How to back up your iPhone, iPad, and iPod touch - Apple Support

Sorry, there's nowhere near enough information here to even begin to guess what your problem is. This is the equivalent of saying 'my car won't start' and expecting someone to be able to tell you what's wrong based only on that...

What happens when you try?

What version of iTunes do you have installed?

What version of iOS are you running on the devices in question?

Are you receiving any error message either on the devices or the computer? If so, what, EXACTLY, does it say?