sending builds online

I’m trying to send a finished build to someone using wetransfer.
it was built on a mac…and I’ve zipped the file.
when they receive the file it comes to show the contents of the build but they’re unable to play the game itself?
what am I doing wrong? how can I send a unity build to someone so they can download it to their computer and play it?
help please?

In “Build Settings” you have to select the target platform it will be run on.