Settings > Shared Folders > Add New Shared Folder
Folder path: <insert_here_hosts_path>
Folder name: <name_of_the_share_on_guest>
Select “Make Permanent”.
Leave unselected “Read-only” and “Auto-mount”.
Make sure the virtual box guest tools are properly installed in the guest machine.
After that, edit /etc/fstab and add the following:
Downloads /home/myuser/Downloads vboxsf rw,exec,uid=1000,gid=1000,dmode=0755,fmode=0644 0 0
This is an example for a shared called “Downloads”.
This share will be mounted under /home/user/Downloads forcing uid/gid to 1000, which it will be the one related to the myuser