It isn’t the easiest feature to turn off but it can still be turned off. Windows Defender isn’t easy to disable users need admin rights to turn it off and it will normally nag a user to enable it again. It also has a nice anti-ransomware feature that not all anti-virus programs have.
It is installed by default, it cannot be removed, and it generally works well to keep a system safe. Windows Defender is the stock antivirus on a Windows 10 system.
