In your Home directory you have a Public folder that can be used to share stuff with other users.
Normally they can only drop stuff in there unless you make it Read and Write.
Unix shares directories and files differently from windows so there is quite a bit to do. Set the File Sharing preferences, in System Preferences/FileSharing to all Windows users to access.
Start by giving Read/Write access to your workgroup and see how you need to progress from there.
If this was just a little home network, you would simply log onto the Mac, across the network, using your own username and password. That way you have total access to all the drives and folders on the Mac.

Try the first way first

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