Windows User: How to make my software compatible for Mac?

I built some software in Python. Works well for windows users using Pyinstaller, but I have a few clients on Mac who want a Mac version. How do I make it compatible to Mac?

PyInstaller can compile a python script only for the target machine on which is installed. (if you install it on Windows, it will compile an exe file on Windows).

That's why you need a Mac. Or you can find somebody with a Mac and ask them to use their device for 2 hours max (given that you'll need to install things on it) and then compile your Mac executable file.