Thanks for stopping by the HP Support Forums! I'd be glad to be of your assistance!
I understand that you are unable to get the Windows 10 drivers for Photosmart 3210 printer. I am afraid that your printer is an older model and hence Windows 8.1 drivers are not available for this model.
I would recommend you use the Windows built-in drivers to tackle this issue. Windows 8.1 OS comes with the built-in printer drivers. Simply turn on the printer and connect the USB cable from the printer to the PC. The drivers will be installed in 2-3 minutes. Go to Control panel - Devices and printers to check the printer entry and make it as default printer if needed.