how to unlock iphone on hp crome laptop

It is not possible, because you can't install iTunes on a Chromebook, you need a Windows OS or macOS computer.

Ask a friend, acquaintance or family to use their computer, or at a public library.

Alternately, visit your local Apple Store or Apple Authorized Service Provider and they should be able to help you out.

You will first have to make an appointment due to the pandemic.

Call Apple in your region see: Contact Apple for support and service

Contact Apple for support and service - Apple Support

If you can download and use iTunes only then you can unlock else no.

You don’t. You need a Mac or Windows PC.