There are various ways to perform host-guest file sharing on runtime: SSHFS, SSH, Samba etc. For internal communications (host - VM under one system), you can use the scary and deadly Samba provided you shielded the host external communications. Otherwise, you may stick to Samba.
First, proceed to setup the file sharing host server.
You can refer to my guide here.
coming soon.
Depending on guest machine's operating system, you can proceed to setup the client interface.
That's all about setting up Host and Guest file sharing system.