1. Install Guest Additions
Open VirtualBox and Start your Virtual Machine.
Click to"Devices" and "Install guest additions"
VirtualBox will a mount a CD with guest additions on your Desktop.
if you have 32-Bit Linux use
if you have 64-Bit Linux use
After you successful installed guest additions reboot your virtual machine.
2. Create Shared Folder
Click to "Devices" and "Shared Folder" on your virtual machine window.
Click to "add Button" and fill in the both fields "Folder Path" and "Folder Name"
Folder Path = D:\sharedFolder
Folder Name = sharedFolder
"Folder Path" ist the path on your Host Machine and "Folder Name" the name of your shared folder in your guest varitual machine.
3. Mount the Folder in your virtual machine.
sudo mkdir /media/sharedFolder
sudo mount -t vboxsf sharedFolder /media/sharedFolder