In the first paragraph, the term “it” refers to

        Windows Defender Firewall helps prevent hackers and malicious software from gaining access to your PC through the internet or a network. Your organization might require you to turn it on before you can access their network resources from your device.

        To turn on Windows Defender Firewall: go to Start and open Control Panel; select System and Security > Windows Defender Firewall; choose Turn Windows Firewall on or off; select Turn on Windows Firewall for domain, private, and public network settings. Still need help? Contact your IT support person. Check the Company Portal website for contact information.

Internet: <https://learn.microsoft.com/> (adapted).