It all comes down to having a multi-channel sound card / audio device (with more than 2 input channels), and the necessary device drivers.
On Windows, the device drivers are frequently the problem. Windows drivers are often 2 channels only, and Audacity cannot ship with ASIO drivers due to licensing problems.
IF you have a multi-channel sound card AND Windows (WDM) drivers for the device that support multiple channels, then it’s simply a matter of selecting the number of channels that you wish to record in the Device Toolbar.
There is some information, provided by Audacity users, about multi-channel sound cards / audio devices here: https://forum.audacityteam.org/t/multi-channel-recording-in-audacity/15644/1