The easy way is to install Windows Live Mail and run Hotmail from there. That offers the benefit of having her mail stored on her PC rather than the Hotamil server. Should she not want to use that option she should sign into Hotmail (or got to the sign in page) and copy the address from the address bar. Go to the Desktop and right click and opt to create a shortcut. Paste the URL in the location box and name the shortcut. Clicking on this con will open Hotmail.
How to get Windows 10 now: how to download and install Windows 10 even if GWX.exe is missing