How to make a Windows folder always available in Ubuntu in Oracle Virtualbox

First share your Windows folder to your Ubuntu virtual machine in Oracle Virtualbox:

In your Ubuntu machine, add a similar line to your /etc/fstab file:

dkuyu   /home/kuyu/dkuyu    vboxsf  uid=kuyu,gid=kuyu,rw,dmode=700,fmode=700,_netdev      0 0

(Be sure to create the Linux folder afterwards. You can do this via mkdir command. In this example, make sure that /home/kuyu/dkuyu exists. If not, create it.)

Reboot your Ubuntu virtual machine.

After reboot, the Windows folder should be available in the Ubuntu folder /home/kuyu/dkuyu (for this example).