Any time I compress a folder into a .zip file, anyone who downloads it on their Windows computer will see a random "_MACOSX" file show up with it. This is a big problem for me because the people I send these to usually don't need to unzip the file to be able to use it. But now they have to in order to take out the file every time, or else it will not work. I would like to know if there is any way to avoid this from happening.
You can exclude all dot files and the "__MACOSX" content by creating the zip file on the command-line with exclusion syntax as shown in this Ask Different article.
You can check if an existing zip file has "__MACOSX" in it from the Terminal command-line. A count (-c) of zero means it does not have the string within it.
zipinfo ./foo.zip | grep -c "__MACOSX"
Simply right clicking on a folder, or multiple, selected files in macOS and choosing compress will include the "__MACOSX" sub-folder references.
"_MACOSX" file showing up from .zip file