Buildozer uses Linux programs. It does not run at a Windows command prompt.
I'm pretty certain none of the documentation says Windows is supported.
However you can get it to run using the Windows Subsystem for Linux. Basically a Bash command prompt.
Install and run Buildozer at this bash prompt. Read the install instructions first.
Its actually kinda cool as you can set your Bash current working directory to your project in the Windows file system.
So nothing changes except running just Buildozer at a different prompt.
You have several choices of Linux systems, I'd suggest Ubuntu 18.04 (I know p4a runs, so I expect Buildozer runs)
Note that on that page in the description it says (I think you have to do it before install the app):
To use this feature, one first needs to use "Turn Windows features on or off" and select "Windows Subsystem for Linux", click OK, reboot, and use this app.
If you are not a Linux user expect some surprises! Really.
You are going to see error messages you don't understand. Remember Google is your friend.
The most likely one is installing additional packages required by some program you run.
Enjoy the learning curve.