Hello TonyG22,
Thank you for posting in Microsoft Community forum.
If the users are only accessing the Windows file share server to upload files and not remotely accessing the server, then a device CAL is not required. Device CALs are typically required for devices that are accessing the server remotely, such as through Remote Desktop Services or other remote access tools.
However, if the users are accessing the server through a network share, then they are not considered to be remotely accessing the server and therefore a device CAL is not required.
I hope the information above is helpful.
If you have any question or concern, please feel free to let us know.
Best Regards,
Haijian Shan