ExpressVPN is based on subscription, but it works with Windows 10, Windows 7, etc. You will need a subscription in order to have access to their servers. Luckily, you can use the Windows 10 manual customization which is also provided on the official website.
Support page: https://www.expressvpn.com/tutorials/windows-10-manual#setup
The developers provide an in-depth guide on how to properly configure the VPN settings.